Xiang Chen

Tsinghua University | TH · School of Materials Science and Engineering

The increase in payload capacity of trucks has heightened the demand for cost-effective yet high performance brake discs. In this work, the thermal fatigue and wear of compacted graphite iron brake discs were investigated, aiming to provide an experimental foundation for achieving a balance between their thermal and mechanical properties. Compacted...

Multiphase stainless steels offer very attractive combinations between strength, toughness and corrosion resistance due to the coexistence of different microstructural components and their interactions. In this study, a novel cast multiphase stainless steel containing martensite, ferrite and austenite was fabricated by a combination of alloy optimi...

Mass Production of Graphene In article number 2203124, Ningzhen Wang, Guqiao Ding, Qingkai Yu, Xiaoming Xie, and co‐workers summarize and discuss the mass production of graphene with the assistance of bubbles. As a new tool, the usage of bubbling makes a big difference in multiple aspects of graphene production. This review sheds light on the intro...

The large‐scale industrial applications of graphene highly depend on its mass production with efficiency (high‐yield, time‐saving, and low‐cost) and controllability (high‐quality, safe, and environmentally friendly). However, this requirement can hardly be satisfied by incumbent chemical exfoliation methods exploiting liquid–solid interactions. Rec...

Cast stainless steels with high strength and toughness are very important for industrial production, but the strengthening methods are very limited. In this study, a novel cast multi-phase stainless steel (CMPSS) containing ferrite, martensite and austenite was prepared and its strengthening mechanism was investigated. After solid solution and temp...

The initiation and propagation of thermal fatigue cracks in gray cast iron and vemicular graphite cast iron were investigated by Uddeholm method to reveal the complex thermal fatigue behaviors of cast iron. Differences of thermal fatigue behaviors of gray cast iron and vemicular graphite cast iron were observed and analyzed. It is found that the ob...

Lotus-type porous Mg–1 wt.% Mn–xZn (x = 0 wt.%, 1 wt.% and 2 wt.%) alloys were fabricated by metal–gas eutectic unidirectional solidification (the Gasar method). Effects of Zn addition and the fabrication process on the porosity, pore diameter and microstructure of the porous Mg alloys were investigated. Zn addition from 0 wt.% to 1 wt.% and 2 wt.%...

In this study, we found that porous CaCl2 granules can be easily deformed under certain pressure and temperature conditions. Based on this finding, a new infiltration process that employs CaCl2 granules as space-holders was developed to prepare aluminum (Al) foam with high porosity. In this process, porous CaCl2 granule preforms were first subjecte...

In order to improve the performance of plaster molds for investment casting, a diverse content of glass fiber and polypropylene (PP) fiber was incorporated into the slurry for the preparation of a fiber-reinforced mold. The green and fired bending strengths, thermal expansion properties, permeability, and thermal shock resistance of the mold were e...

Directionally solidified porous copper is considered as a potential candidate in the field of microchannel heat sinks. By the Bridgman-type directional solidification method, a porous copper ingot was fabricated. Evolution of the porosity, pore number density, average pore diameter and average interpore spacing at different ingot heights was invest...

Magnetic field annealing (MFA) was used to tailor the magnetostriction and magnetic domains of Fe80Ga16Al4 alloy, and the relationship between the two characteristics was studied. The <100>-oriented alloy was prepared by the directional solidification technique and annealed for 20 min at 700 °C in a magnetic field of 250 mT along a direction 45° to...

Open-cell metallic foams or porous metals have a distinctive combination of excellent structural performance and superior functional characteristics, such as their light weight, energy absorption, sound absorption, heat dissipation, and electromagnetic shielding. As the primary representative of metallic foams, the aluminum foam has developed into...

Lotus-type porous Mg–xMn (x=0, 1, 2 and 3 wt.%) alloys were fabricated by metal/gas eutectic unidirectional solidification (the Gasar process). The effects of Mn addition and the fabrication process on the porosity, pore diameter and microstructure of the porous Mg−Mn alloy were investigated. Mn addition improved the Mn precipitates and increased t...

Understanding the correlation between cell deformation and initial cell structure during compression is important for improvement and development of effective applications of aluminum foams. Foams with porosities lower than 75% now get more attention because of more spherical cells and better mechanical performance. Herein, two low porosity aluminu...

Fe83Ga17 alloy is a kind of promising magnetostrictive alloys with high magnetostrictive properties and a low saturation magnetic field. As-cast Fe83Ga17Dyx (x=0, 0.05, 0.1, 0.2, 0.4) polycrystalline alloys were prepared by arc melting. Effect of Dy doping on the microstructure, magnetostrictive and mechanical properties of as-cast Fe83Ga17 alloy w...

In the melt foaming process of aluminium foams, small pore size aluminium foam is difficult to fabricate, this is mainly due to the early decomposition and poor dispersion of foaming agent (usually TiH2). In this study, these two problems are solved concurrently by introducing a TiH2-AlMg35 composite foaming agent in the melt foaming process. The c...

Lotus-type porous Mg-Mn alloys were fabricated by solid-gas eutectic unidirectional solidification (the Gasar process) by controlling and optimizing the process parameters. The microstructures, compressive properties and corrosion properties in a simulated body fluid solution were investigated. Porous pure Mg was prepared with a preferentially orie...

In order to find out the most effective method for developing compacted graphite iron with a combination of high tensile strength, ductility and thermal conductivity, the superposed structural effects were investigated by experimental results and the relative significances were ranked on the basis of fuzzy neural network model. The concerned struct...

A special kind of microchannel heat sink is fabricated by a lotus-type porous copper in which long cylindrical pores are arranged in one direction. By applying the straight fin model to the lotus-type porous copper, the effect of the pore structure including porosity, pore diameter and open porosity on its heat transfer performance can be predicted...

A quantitative model is proposed to describe the thermal conductivity of alloyed pearlitic gray cast iron. The model is built by combining the computational thermodynamics and effective medium theory. The volume fractions and concentrations of precipitated phases in as-cast structure are estimated in consideration of partial and para-equilibrium. T...

The effects of Mo and Ni on the microstructure and properties of compacted graphite iron were investigated experimentally, especially with regard to the thermal conductivity at elevated temperature. It was found that the ferrite fraction is weakly affected by Mo content but significantly reduced by Ni addition. Moderate content of Mo is beneficial...

This paper summarizes melting methods of titanium and titanium alloy, such as vacuum arc melting (VAR) and electron beam cold hearth melting (EBCHM), and the related inclusions formed when using these melting methods. Low-density inclusions are resulted from contamination of air, and high-density inclusions are caused by refractory elements. The fo...

To develop a high performance gray cast iron with high tensile strength and thermal conductivity, multivariable analysis of microstructural effects on properties of gray cast iron was performed. The concerned parameters consisted of graphite content, maximum graphite length, primary dendrite percentage and microhardness of the matrix. Under the sup...

In this paper, 7050-T7451 C-Ring stress-corrosion alternate immersion test in neutral 3.5% NaCl solution was conducted to investigate the mechanism of stress-corrosion cracking (SCC). The SCC sequence was proved to comprise dealloying, pitting, micro-cracks, and intergranular (IG) cracks. Besides, anodic dissolution characterised by reticular IG cr...

With the aim of improving the thermal conductivity and tensile strength of pearlitic gray cast iron, the influence of inoculation on structure and properties was experimentally investigated. Three group of irons with similar compositions were inoculated by Zr-FeSi, Sr-FeSi, and SiC inoculants, respectively. The metallographic analysis was used to m...

The dynamic gas injection method with high-speed horizontal oscillation could reduce the cell size and improve the cell quality of aluminum foams, so it is of interest to study the compressive performance and deformation mechanism of the foams produced with this process. In-situ compression in X-ray tomography was used for this research. Results ha...

The previous studies have revealed that addition of different elements in TbDyFe alloys have different influences on its microstructure, mechanical and magnetic properties. According to the effects, one can classify elements into different groups. This paper aims to explain the differences by the enthalpy of mixing between the atomic pairs. Various...

The mold pressing process was applied to investigate the formability of closed-cell aluminum foam in solid–liquid–gas coexisting state. Results show that the shape formation of closed-cell aluminum foam in the solid–liquid–gas coexisting state was realized through cell wall deformation and cell movement caused by primary α-Al grains that slid, rota...

The intrinsic brittleness of the TbDyFe alloy significantly decreases its mach inability and applications. This paper aims to improve the toughness of TbDyFe alloy by adding Cu. Various alloys of the type (Tb0.3Dy0.7)0.37Fe0.63–xCux (x = 0, 0.01, 0.03, 0.05, 0.08, 0.1) were fabricated by an arc melting furnace under a high purity argon atmosphere....

Quasi-static uniaxial compressive experiments were conducted on aluminum foams with a wide range of relative densities (0.134-0.472). The compressive properties and energy absorption capacity were systematically characterized and compared in a more suitable way. The compressive stress instead of compressive strain achieved during energy absorption...

This study mainly investigated the influence of Calcium (Ca) addition on the pore size of aluminum foams made by using Cu–TiH2 composite powder as foaming agent. The Ca addition required for fabricating aluminum foams with different pore sizes was experimentally investigated. Two possible foam stabilization mechanisms were discussed and compared. F...

The influence of Si, Sn, Mo and Ni on the ductility and thermal conductivity of compacted graphite iron (CGI) was investigated. Metallographic observation and Differential Scanning Calorimetry (DSC) experiments were carried out to analyze the roles of various additions in the eutectoid reaction. The experimental results showed that the ductility of...

The uniformity of the cell size of aluminum foams prepared by traditional melt foaming and gas injection methods is difficult to control. In order to improve the controllability of cell size and mechanical performance of aluminum foam, an A356 matrix syntactic foam was prepared by the improved stir casting process. Moreover, the compressive propert...

Compared to traditional pore structure with high porosity (≥ 80 pct) and large pore size (≥ 3 mm), aluminum foams with low porosity (60 to 70 pct) and small pore size (≤ 2 mm) possess higher compressive property and formability. In order to achieve the goal of reducing pore size, Cu-TiH2 composite powder prepared by ball milling preoxidized TiH2 wi...

Aluminum foams are new kind of structural-functional composite materials which comprised of aluminum matrix and gas pores. In this paper, aluminum foams with homogeneous pore structure made by 6063 aluminum alloy were fabricated by melt foaming method. As comparison, the aluminum foams were also fabricated by pure aluminum. Studies on process param...

The cell structure and mechanical properties of aluminium foams prepared by melt foaming (MF) method are supposed to be better than the ones produced by gas injection (GI) method. Preparation processes of these two methods have been developed during the last recent years. Mechanical properties of aluminium foams depend strongly on characteristics o...

This paper describes a new method for optimizing the cellular structure of AlMg4Si8 alloy foams manufactured via powder metallurgy. The cellular structure was improved by pretreating TiH2 with a layer of Sn powder, which was then remixed with an AlMg4Si8 alloy used as the raw material for the preparation of the precursor. TiH2 was completely encaps...

The intrinsic brittleness in giant magnetostrictive material TbDyFe alloy has devastating influence on the machinability and properties of the alloy, thus affecting its applications. The purpose of this paper is to study the mechanical properties of the TbDyFe alloy by alloying with Nb element. The samples (Tb0.3Dy0.7)xFe2xNby (y = 0, 0.01, 0.04, 0...

A new Ni-based superalloy with high-Cr content was designed for industrial gas turbines application. The microstructural homogenization and high-temperature cyclic oxidation behavior was investigated systematically. The results showed that the optimum heat treatment condition was 1563 K (1290 °C)/4 h + 1573 K (1300 °C)/6 h, A.C. (air cooling) + 139...

The favorable energy absorption characteristics of foam structures originate from their layer-by-layer deformation behavior. In this paper, the effects of cell morphology on the compressive performance of thinwalled aluminum foams were studied by a finite element method using a three-dimensional, thin-shell Kelvin tetrakaidecahedron model. Models w...

The reduction of cell size is beneficial to the stability and mechanical properties of aluminum foams. The cell size could be effectively reduced by dynamic gas injection route, but the smaller cell size is also required for the smaller particle size and more uniform dispersion of ceramic particles. The gas injection route and the preparation of fo...

Mg-Li alloy is a unique system with a narrow dual-phase region and superstructure transformation. These characteristics will have significant influence on the solidification behavior. Using Bridgman-type vacuum furnace with liquid metal cooling method, the directional solidification experiments were performed on alloys with different Li contents (6...

Aluminum foams made by 6063 aluminum alloy have been prepared by melt foaming method. The uniformity of foam pores is much concerned for that homogeneous pores attribute to excellent properties. It is mainly up to the stirring intensity when adding the blowing agent into the melt, and the cooling rate of the liquid foams. In this paper, 6063 alumin...

This article introduces an improvement to the fabrication of aluminum foams with small pore size by melt foaming method. Before added to the melt, the foaming agent (titanium hydride) was pretreated in two steps. It firstly went through the traditional pre-oxidation treatment, which delayed the decomposition of titanium hydride and made sure the di...

HfMo0.5NbTiV0.5Six (x = 0, 0.3, 0.5, 0.7) high-entropy alloys are synthesized by induction levitation melting with the aim of achieving a balanced combination of excellent strength at elevated temperature and reasonable ductility at room temperature (RT). The microstructure, phase evolution and compression mechanical properties of the alloys from 2...

Reducing the cell size of aluminum foams is always a hot and difficult topic in the fabrication of aluminum foams by gas injection route. There lacks theoretical guidance for the bubble size reduction when foaming by the dynamic gas injection method. For the convenience of observation, the aqueous bubbles from small-sized orifice in the high-speed...

A new refractory alloy HfNbSi0.5TiVZr was synthesized by induction levitation melting with the aim to achieve an excellent strength and toughness balance of the Hf-Nb-Ti-Zr based alloy. The as-cast alloy with density of ρ=7.75g/cm³ and microhardness of Hv=464 had the microstructure consisting of bcc solid solution with little vanadium rich phase an...

The bubble generation process in conditioned A356 alloy melt through submerged spiry orifices with a wide diameter range (from 0.07 to 1.0 mm) is investigated in order to prepare aluminum foams with fine pores. The gas flow rate and chamber pressure relationship for each orifice is first determined when blowing gas in atmospheric environment. The e...

As an excellent giant-magnetostrictive material, Tb-Dy-Fe alloys (based on Tb0.27-0.30Dy0.73-0.70Fe1.9-2 Laves compound) can be applied in many engineering fields, such as sonar transducer systems, sensors, and micro-actuators. However, the cost of the rare earth elements Tb and Dy is too high to be widely applied for the materials. Nowadays, there...

High-temperature mechanical properties of high-boron austenitic steels (HBASs) were studied at 850 °C using a dynamic thermal-mechanical simulation testing machine. In addition, the thermal fatigue properties of the alloys were investigated using the self-restraint Uddeholm thermal fatigue test, during which the alloy specimens were cycled between...

A new composite structure based on aluminum foam sandwich and fiber metal laminate was proposed. A layer of glass fiber was provided at the interface between the metal panel and the aluminum foam core in this composite structure, using adhesive technology to bond the materials together by organic glue in the sequence of metal panel, glass fiber, al...

The Joint Conferences of 2015 International Conference on Computer Science and Engineering Technology (CSET2015) and 2015 International Conference on Medical Science and Biological Engineering (MSBE2015) Hong Kong, 30 – 31 May 2015 Edited by: Jiamei Deng ( Kingston University, UK), Qingjun Liu ( Zhejiang University, China) The differences of two m...

A bimodal porous Cu with regular Gasar micrometer or millimeter pores and random dealloying nanometer pores was fabricated by chemical corrosion of Cu–Zn alloy layers on the inner surface of Gasar Cu pores. In order to accomplish this object, a two-step corrosion method was conducted, including the selective corrosion of Zn element from Cu–Zn alloy...

Copper die-casting die steel is usually used in severe rugged environment. Liquid metal flows with high temperature and high pressure during injection and provides rapid filling of the die cavity. The copper die-casting steel should has excellent combination of the properties of high toughness, wear resistance, hardness, thermal fatigue resistance,...

Copper die-casting die steel is usually used in severe rugged environment. Liquid metal flows with high temperature and high pressure during injection and provides rapid filling of the die cavity. The copper die-casting steel should has excellent combination of the properties of high toughness, wear resistance, hardness, thermal fatigue resistance,...

The present study proposed a convenient method to characterize the stability of aluminum foams by utilizing the resulting foam height. The factors influencing foam height in gas injection process was investigated including the blowing gas (N2 and air), particle content (5vol.%-15vol.%), gas flow rate (0.03m3/h-0.3m3/h) and orifice size (0.3mm and 0...

The influences of parameters on the bubble size in aluminum alloy melt during the gas injection foaming process were studied. The four parameters were the orifice diameter (0.4-3.0 mm), the orifice numbers (1 and 4), the gas chamber volume (11-800 cm3), and the gas flux (10-282 L/h). It was found that the bubble size decreased with the decrease of...

A kind of austempered boron alloyed high silicon cast alloy was developed though modification with Ti and controlling austempering temperature, the impact toughness of which increases to 20.7 J/cm2, which is more than triple that of the previous work. The alloy with modification exhibits obvious grain refining both in matrix and boride, improved th...

The uniaxial compressive stress–strain behavior of low density, closed cell aluminum foam by gas injection method has been measured and analyzed in terms of its microstructure and fracture morphology. The experimental results have shown that the stress–strain curve fluctuates drastically in the plateau region and that the influence on compression p...

A new type of austempered boron alloyed high silicon cast steel has been developed. The microstructure and mechanical properties of the boron alloyed high silicon cast steel austempered at different temperatures have been investigated. The experimental results indicate that the boron alloyed high silicon cast steel comprises a dendritic matrix and...

A new type of Fe-C-Si-B alloy was developed. The investigation on microstructure details and the mechanical properties were performed for different austempering combinations. The results indicated that the Fe-C-Si-B alloy comprises ferrite, pearlite and interdendritic eutectic borides in as-cast condition. The distribution of eutectic boride with a...

The compressive properties of aluminum foams by gas injection method have been investigated under both quasi-static and dynamic compressive loads. The experimental results indicate that the deformation of the aluminum foams will go through three stages: elastic deforming, plastic deforming and densifying stage in both the quasi-static and dynamic c...

A new type of austempered high boron white cast iron was developed. The microstructure details and the mechanical properties were performed for different austempering combinations. The experimental results indicate that the austempered high boron white cast iron comprises ferrite, pearlite and interdendritic eutectic borides in as-cast condition an...

It was presented that there must be some melt residual in batch type gas injection foaming process of aluminum. And it was proved by experiments. The differential equation of particle content and gas injection depth in the batch type process was presented, by which the melt residual ratio was predicted with the stability criterion equation as bound...

The bubble formation at a submerged orifice in the process of aluminum foams produced by gas injection method is investigated. The experimental results show that the increase of the gas flow rate and the orifice diameter can lead to increasing of the bubble size. The large orifice can make the frequency of bubble formation decrease by slowing down...

The A356 alloy foams were fabricated by gas injection method. The high-speed stirring and continuous addition of Al2O3 particles were used to solve the problems of non-uniform distribution of Al2O3 particles. The static orifices were designed to blow the compressed air into the aluminum melt by controlling the gas circuit. The stable aluminum foams...

The microstructure and mechanical properties of high boron white cast irons with about 4wt% chromium before and after treating with rare earth magnesium alloy were studied in this article. The experimental results indicate that the cast irons comprise a dendritic matrix and interdendritic eutectic borides M2B and M′0.9Cr1.1B0.9 that distributed in...

The effect of Ca addition on particulate dispersion and foam stability in gas injection foaming process was investigated. The particulate size in the melt, the critical injection depth, the thickness of foam cell wall and the wetting angle of Al2O3 particulate on the bubble surface were viewed without and with Ca addition into A356 melt, respective...

Aluminum foams with various cell sizes and porosities were prepared by the melt foaming process. The sound absorption properties of aluminum foams with different porosities in as-received state and with drilling holes of 1.1 mm diameter were investigated. The results show that the aluminum foams in as-received state with no back cavity do not posse...

Particle coverage ratio on bubble interface was investigated by metallographic analysis when the foam is critically stable in the gas injection foaming process. It is found that the critical coverage ratio was almost the same under different conditions, such as different particle amount, particle size, or particle wettability. The particle coverage...

The effect of different tempering temperatures on the microstructure and mechanical properties of high boron white cast iron after air quenching was studied. The experimental results indicate that the high boron white cast iron comprises a dendritic matrix and interdendritic boride M2B that distributed in the form of continuous network and the matr...

Effects of boron and strontium combined treatment on the microstructure of hypoeutectic Al-7Si alloy have been studied. Experimental results show that strontium has no significant effect on the grain refinement efficiency of boron and the eutectic silicon modification efficiency is not only related to the strontium content but also related to the b...

The acoustic properties of aluminum foams by gas injection method were studied experimentally. The micro and macro structure of aluminum foam with closed cells were observed by optical microscope (OM) and scanning electron microscope (SEM). The special structure of the closed-pores of the aluminum foams have leaded to good performance of the sound...

Metallic foams of A356 alloy with a uniform porosity of 75-85% were produced with the melt foaming process. The microstructure inside the foam cell walls was experimentally studied. It is found that the microstructure is greatly different from the as-cast structure of the base alloy. It is believed that the thickening process with calcium, the addi...

The in-situ X-ray diffraction observations of the bainitic transformation of silicon alloyed steels were performed using the high temperature X-ray diffraction technique. The experimental results have shown that the volume fraction and carbon content of austenite remains a constant value which indicate that the transformation is almost finished aft...

The microstructure and mechanical properties of AlxCoCrCuFeNi with different Al content have been studied. The results showed that the microstructures exhibit simple dendrite and interdendrite structures. When the content of aluminum was low, the alloy was composed of a simple FCC solid-solution structure. As the aluminum contents increasing, a BCC...

The in-situ X-ray diffraction observations of the bainitic transformation of high silicon cast steel were performed using the high temperature X-ray diffraction technique. The volume fraction and carbon content of austenite depend on the transformation temperature. The experimental result has shown that the volume fraction of austenite ceases to a...

Crack initiation, propagation and microfracture processes of austempered high silicon cast steel have been investigated by using an in-situ tensile stage installed inside a scanning electron microscope chamber. It is revealed that micro cracks always nucleate at the yielding near imperfections and the boundary of matrix-inclusions due to the stress...

High boron iron-based alloy, a new kind of wear-resistant material was developed, and its microstructure and mechanical properties were studied. Moreover, the modification with V, Ti and RE-Mg was carried out as well. The results indicate that the high boron iron-based alloy comprises a dendritic matrix and interdendritic eutectic bo-rides under as...

The in situ x-ray diffraction observations of the bainitic transformation were conducted by using the high-temperature x-ray diffraction technique. The volume fraction and carbon content of austenite depend on the transformation temperature. The d{110} value of bainitic ferrite decreases with increasing austempering temperature, which is related to...

The batch preparation of A356 alloy foam slabs with various thicknesses (500×1000×X) was realized by melt foaming process. The key technologies of the process, including melt thickening, blowing agent adding and the foam uniformity controlling were systematically studied. The optimized process parameters for preparing A356 alloy foam blocks and sla...

With boron substituting for carbon in cast iron composition and eutectic borides substituting for eutectic carbides in microstructure as the hard wear resistant phase, a new kind of wear resistant white cast iron has been developed. The microstructure and mechanical properties of this new white cast iron both in the as cast state and after appropri...

In this paper, high boron white cast iron, a new kind of wear-resistant white cast iron was developed, and its microstructure and mechanical properties were studied. The results indicate that the high boron white cast iron comprises a dendritic matrix and an interdendritic eutectic boride in as-cast condition. The distribution of eutectic boride wi...

The shape of the freezing zone of a thermal analysis cooling curve not only contains the information about the modification level of compacted graphite cast iron (CGI) right after vermicularizing treatment, but also reflects the following fading process during holding. When the freezing zones of two cooling curves are approximately the same, graphi...

In this article, the effect of chromium on microstructure and properties of high boron white cast iron was studied. The results indicate that the microstructure of high boron white cast iron with different chromium content comprises a dendritic matrix and interdendritic eutectics, and the eutectic compound has a M2B-type chemical formula that does...

A melt quality evaluation system, based on the pattern recognition of the thermal analysis cooling curves and database technique, has been developed to evaluate the modification level and predict the graphite morphology in compacted graphite iron (CGI). It is verified that when the comprehensive difference parameter Ω, which presents the difference...

High boron iron-based alloy (HBIA) is a kind of new wear-resistant material. Boron and carbon are the important elements that can decide boride and matrix respectively, and their contents affect the microstructure and properties of the HBIA greatly. An orthogonal experiment was adopted to study microstructure, hardness and impact toughness of the H...

The as-cast microstructures of high boron iron-based alloy samples solidified in investment mould and metal mould all comprises dendritic matrix and interdendritic eutectic boride Fe2B. With increasing cooling rate, the size of dendritic matrix is decreased, and the morphology of Fe2B is changed from fishbone form to mesh form, and the boride is di...

The effects of austempering on the microstructures and mechanical performances of cast high carbon silicon and manganese steel (HCSMS) containing 1.0 wt.%C-2.5 wt.%Si-1.5 wt.%Mn-1.0 wt.%Cr-0.5 wt.%Cu were studied. The test results show a plate-like morphology of bainitic ferrite. Each plate of the ferrite is surrounded by a thin layer of retained a...

High boron iron-base alloy is a new kind of wear-resistant material, which takes high hardness and brittle eutectic borides as its wear-resistant phases. However, eutectic borides are distributed in the shape of net at grain boundary and result in a low ductility. Changing the morphology of borides is an effective way to increase ductility. In this...

The microstructure, tensile and impact behaviour of high-carbon Si-Cr cast steel containing rare earth (RE) and titanium have been determined after austempering. The additions of RE and titanium refined the primary austenite grain size resulting in improving toughness. The addition of silicon handicapped the formation of carbide and carbide-free ba...

The microstructure and morphology of retained austenite of austempered high silicon cast steel after various austempering combinations are investigated by TEM, and the volume fraction of retained austenite is measured by XRD method. The experimental results indicate that the retained austenite presented at the isothermal transformation temperature...