Smith Salifu

University of Johannesburg | uj

This review paper encompasses a comprehensive exploration of fatigue failure and fatigue life estimation techniques which spans from the classical methods to new and innovative approaches. The paper looks into the limitations and advancements of these techniques and highlights their respective strengths and areas for improvement. Some of the models...

Investigating the structural behaviour and buckling susceptibility of cylindrical oil storage tanks is crucial for ensuring their safe and reliable operation. In this study, the structural behaviour and buckling susceptibility of closed roof-top cylindrical oil storage tanks under combined internal and external pressure scenarios were investigated...

This study investigates the design, phase identification, and microstructural properties of high-entropy alloy (HEA)-reinforced aluminium (Al) matrix composites. Thermophysical expressions for HEAs were employed during the design phase of the HEA; both theoretical frameworks and experimental analyses were used to anticipate stable phases while a fi...

Spark plasma sintering (SPS) technique was employed in the consolidation of Cr20Mn20Ni20Cu20Nb10Co10 high entropy alloy (HEA) reinforced aluminium matrix composites. Phase stability and prediction expressions were used in the determination of the powder combination for the HEA. The microstructural analysis showed that an interdiffusion layer was fo...

With the continent of Africa occupying the front seat of underdevelopment in the world, and its population increasing exponentially, there is an urgent need to come up with strategies to tackle the underdevelopment ravaging the continent and the demand posed by its constantly growing population. Engineering through appropriate engineering education...

The enormous composition possibilities and the potential of developing alloys with improved properties have resulted in a spike in research interest in the area of high entropy alloys (HEAs) since 2010. Being multicomponent alloys with five or more metallic elements mixed in equimolar or non-equimolar ratio, HEAs offer limitless possibilities in th...

Materials properties are highly dependent on the processing parameters and technique used during sintering. The effect of Spark Plasma sintering process parameters (pressure and temperature) on the hardness and relative density of Ni-20Cr-5ZrO2 composite was investigated. Response Surface Methodology (RSM) from the design of experiment (DOE) techni...

While IN738 Ni-based superalloy is a high strength alloy, it is feasible to improve its properties at the bulk level by reinforcing with graphene nanoplatelets (GNPs), taking advantage of the superior mechanical, tribological and thermal properties using the spark plasma sintering technique. In the present study, the influence of spark plasma sinte...

The quest to replace glass with transparent aluminium ceramics (AlON) in some applications such as automotive, aircraft, armour, electronics, mobile phone screens, etc., is long in coming. More than ever, the dire need for this replacement is calling for urgent attention in the research world. Some years ago, the possibility of fabricating transpar...

The introduction of computational modelling during alloy development has significantly reduced the cost of production and the prolonged time spent by researchers doing trials and errors in the laboratory. In this study, computational software (JMat Pro) was used to simulate the effect of the addition of Zr and Co, on the material properties of NiAl...

The accurate prediction of the thermomechanical properties of newly developed polymer composites is important in the determination of their possible areas of application. In this study, a 3D model of representative volume element (RVE) with different wood flour weight ratios (5, 10, 15, 20, 25 and 30 %) was used to develop wood flour polymer compos...

Environmental conservation and waste control have informed and encouraged the use of biodegradable polymeric materials over synthetic non-biodegradable materials. It has been recognized that nano-sized biodegradable materials possess relatively good properties as compared to conventional micron-sized materials. However, the strength characteristics...

As a promising technology capable of transforming the conventional manufacturing techniques, the use of additive manufacturing (AM) has span beyond the prototyping it was initially known for, and its use is currently revolutionising the future of the manufacturing and research world. A review of some of the advances made in the additive manufacturi...

Ni-Cr-ZrO 2 composites with varying amounts of ZrO 2 additive (5 wt%, 7.5 wt%, 10 wt% and 12.5 wt%) were fabricated using spark plasma sintering method at a sintering temperature of 1000°C, heating rate of 100°C/min, holding time of 5 min, and a pressure of 50 MPa. The effect of ZrO 2 addition on the microstructure, tribological and mechanical prop...

This study investigates the influence of residual stresses induced by the manufacturing process, on the fatigue life prediction of micro gas turbine blades manufactured by laser metal deposition additive manufacturing technique and heat-treated at different heat-treatment parameters. Finite element modelling, using commercial software Abaqus CAE ®...

The microstructure, mechanical and tribological properties of Ni-Cr-ZrO2 composites, manufactured by using the spark plasma sintering technique with different sintering temperatures, were investigated. The individual powder was measured and mixed thoroughly in a tubular mixer for 8 hours before being transferred to the sintering machine. The sinter...

Additive manufacturing (AM) of polymer-based composites in the automotive industry has enjoyed tremendous progress in recent times. The use of this manufacturing technique has made it possible for the manufacturing of cost-effective, single, complex and customized automotive components. Of all the available additive manufacturing techniques, stereo...

The effects of the addition of different percentage compositions of graphene nanoplatelets (GNPs) to a nickel-based superalloy were investigated in this study. A spark plasma sintering (SPS) method was employed in the development of the nickel-based alloy/composites, and the developed bulk nickel-based alloy and its composites were from high-purity...

This work investigated the dry sliding wear behaviour of spark plasma sintered (SPSed) Ti-Ni binary alloys produced at varying nickel content with alloy steel ball as the counterface material, at room temperature under varied applied normal loads. Finite element modeling was used to investigate the high-velocity impact response of the sintered allo...

The creep response and stress relaxation of X20 CrMoV12-1 steam piping under diverse operating conditions were simulated using finite element analysis (FEA) code, Abaqus alongside fe-safe/Turbolife software. In the study, steady-state creep and creep analysis characterized by 24 hours daily cycle consisting of a total of 6 hours peak, 4 hours trans...

Steam piping is one of the major components of power generation plant because of its use in conveying steam from the boiler to the turbines compartment. Over time, these pipings are subjected to diverse operating conditions in an attempt to meet the daily electricity demand. Hence, the useful creep life of the piping is drastically affected. In thi...

In a bid to minimise the cost of electrical energy production through the reduction in the quantity of coal usage, the power generation companies resolved to operate different daily cycles characterized by peak and off-peak energy demand periods. These daily operational cycles have left the power plant components operating in a possible creep-fatig...

In this study, effect of mechanical milling on the mechanical, dry sliding wear and impact response of spark plasma sintered Ni-17Cr6.5Co1.2Mo6Al4W7.6Ta superalloy has been investigated. Two nickel-based superalloy were sintered, firstly in their as-received elemental particle sizes, while the matrix, nickel of the second alloy, was milled to 10 h...

In service, steam pipes are subjected to high temperature close to 0.4 Tm (melting temperature) or higher and pressure; thus, making them prone to failure due to creep. Often, the design methods for these steam pipes usually do not provide their specific in-service life; hence, some type of service fitness tests are performed, and data obtained fro...

The consolidation of polylactic acid/graphene nanocomposite via a novel SPS powder metallurgy route was elaborated in this study. The nanocomposite powders were prepared using the three-dimensional (3-D) tubular mixer and consolidated under different parameters of spark plasma sintering (SPS). The densification, porosity, hardness, and crystalline...

The geometrical increase in the demand for electrical energy has posed serious pressure on the power generation components such as the steam pipes due to the consequential increase in the operating parameters such as temperature and pressure. This increment in operating parameters tends to limit the useful life of these pipes. Thus, high creep resi...

The possibility of creep–fatigue interaction occurring in steam pipes of power generation plants during operation has been on the front burner for years. Often, failure of the pipes during operation is attributed to either creep alone or fatigue alone. Of recent, some failures are speculated to be due to simultaneously coupled interaction between c...

Creep behaviour of X20 (12Cr-1MoVNi) steam piping subjected to a typical operating pressure of 18 MPa and temperature of 550 °C have been investigated using finite element analysis code, Abaqus and fe-safe/Turbolife software. User subroutine script for the modified hyperbolic sine creep model used was developed in Fortran and implemented in Abaqus....

Components subjected to operation at a temperature in the range of 0.4 Tm (Melting temperature of component) and above are prone to failure due to creep. The failure becomes more severe when the component is further subjected to a sequence of start-up and shutdown cycles. If the cycles are enough to induce extensive plastic strain, the failure of t...

Flanges are vital component used in power generation plants for linking, closing and connecting of pipes to the boiler and turbine compartments. The linking of piping networks via this approach has limited the use of welding in the industry. High temperature, pressure and thermal transitions are presumed to influence the behaviour of bolted flange...

The quest to reduce the energy consumption in automotive has resulted in the development and use of lightweight materials for the design of vehicles. Also, stiffer legislation is being put in place to enforce the utilization of lightweight components for vehicles in order to guarantee the safety of both pedestrians and passengers. Hence, the bumper...

Graphene/Inconel 738LC composites were synthesized using spark plasma sintering technique and the microstructural features were investigated using Optical microscope, Scanning electron microscope and X-ray diffraction machine. The microhardness, porosity and fracture toughness of the graphene-reinforced Inconel 738LC matrix composites were obtained...

The spark plasma sintering technique (SPS) was used to consolidate admixed elemental powder in order to fabricate NiCrCoAlTiW-Ta superalloy. Nickel which is the key element that formed the matrix powder particle size was varied in the range of 3-44, 45-106 and 106-150 μm. The effect of varying the starting powder particle size, on the formation of...

The thermo-mechanical stress, strain and temperature distribution across the thickness of X20 steam pipe at region less susceptible to thermo-mechanical failure was simulated using finite element analysis software, Abaqus. The mesh convergence studies conducted showed that 10 mm mesh size was suitable for the simulation. The temperature distributio...