Effects Of Heat-treatment On Microstructures And Mechanical Properties Of Wo_3 Particle And Al_(18)b_4o_(33) Whisker Hybrid Reinforced Al Matrix Composites By Squeeze Casting

摘要

In this paper, WO_3p and Al_(18)B_4O_(33)W hybrid reinforced aluminum matrix composites were fabricated by squeeze casting. Heat-treatment of the composites was carried out at 500 ℃ for different times. Gibbs free energy calculation indicated that the reaction of WO_3 with Al was spontaneous. DTA result showed that the reaction of WO_3 with Al took place at 396 ℃ and 487 ℃. XRD results showed that the interfacial reaction occurred after heat-treatment at 500 ℃ for 5 h and 10 h and the reaction products were WO_(2.90) and WO_(2.83). which resulted in the formation of micro-voids at the interface between particle and matrix and led to mechanical properties of the composites decreasing. However, mechanical properties of the composites heat-treated for 10 h did not decrease obviously compared with that of heat-treated for 5 h. The reason may be that the produced aluminum oxide film covered the WO_3p and retarded progress of the chemical reaction.