MECHANICAL AND THERMAL PROPERTIES OF INFILTRATED 3D-Si_3N_4 COATED SiO_2/ Al-Mg-Si AND Si_3N_4/Al-Mg-Si ALLOYS BY PRESSURELESS INFILTRATION

摘要

The effect of processing parameters on the pressureless infiltration of Si_3N_4 and coated SiO_2 preforms by aluminum alloys has been investigated. The effect of atmosphere, infiltration time, temperature, porosity of perform, and Si_3N_4 coating on the SiO_2 particles, on the pressureless infiltration of rice husk ash preforms with aluminum, was investigated and quantified via a Taguchi experimental design and ANOVA. The contributions of each of the parameters and of their interactions on module of elasticity, hardness and thermal diffusivity of the composites were determined. The maximum modulus of elasticity and hardness obtained were 265 GPa and 842 HV, respectively. The thermal diffusivity of four fabricated samples (two samples with the highest and two samples with lowest electrical resistivity) was measured. The results show that the composite with the highest value of electrical resistivity has the highest value of thermal diffusivity (20.4 mm~2/s).