Schematic of diffusion bonding process [7] 

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... of the fibre orientation and any process of chemical bonding, the rule of mixtures is interpreted as a simple volumetric mixture of properties. For a preliminary evaluation of the behaviour of Mg-B (20%) composites, the upper and lower limits of CTE using rule of mixtures are calculated as  c  13 . 62 x 10  6 / o C and  c  20 . 81 x 10  6 / o C respectively. The upper and lower limits of CTE according to the rule of mixtures were within the range of CTE in longitudinal and transverse directions using Schapery model. The plates of Mg-B (20%) composites were produced by the process of diffusion bonding occurred between matrices and fibres. In this bonding process atomic inter- diffusion occurs between the surfaces in contact when it reaches to certain temperatures and levels of pressure/vacuum. The main advantage of this bonding process is controlling the fibre orientation and the volume fraction [7]. The process starts with a coordinated distribution of fibres in the blades of the array. Then these sheets stack between the matrix. Compression in vacuum chamber provides the adhesion between the contact surfaces of the blades of the matrix and the fibres for subsequent atomic diffusion at high temperatures. The process is schematically shown in Fig. 1. The diffusion bonding process in a vacuum chamber is shown in Fig. 2. The samples of 12.45mm length, as shown in Fig. 3, were cut using ISOMET precision cutter with diamond discs. The maximum width of samples is limited to 8mm due to restrictions of the o o dilatometer. The samples were cut to produce 0 , 60 and o 90 fibre orientations. The samples were held in a NETZSCH DIL 402C dilatometer. A temperatures range of 32 o C – 520 o C with a o heating rate of 5 C/min was considered. The samples and equipment were cooled naturally to reach room o temperature (25 C). The CTE obtained through o experimental samples with 0 , 60°, and 90° ...