Al2O3/TiB2/Al复合材料的微观结构和高温力学性能

以细雾化铝粉和TiB₂颗粒为原料,通过粉末冶金和热轧制制备微米TiB₂和纳米Al₂O₃颗粒增强铝基复合材料。室温时,由于TiB₂和Al₂O₃的综合强化作用,Al₂O₃/TiB₂/Al复合材料的屈服强度和抗拉强度分别为258.7 MPa和279.3 MPa,测试温度升至350℃时,TiB₂颗粒的增强效果显著减弱,原位纳米Al₂O₃颗粒与位错的交互作用使得复合材料的屈服强度和抗拉强度达到98.2MPa和122.5 MPa。经350℃退火1000 h后,由于纳米Al₂O₃对晶界的钉扎作用抑制晶粒长大,强度和硬度未发生显著的降低。

Microstructure and elevated temperature mechanical properties of Al2O3/ TiB2/Al composites

Aluminum matrix composites with micro-TiB₂ and nano-Al₂O₃ particles were successfully fabricated by combining powder metallurgy and hot rolling using raw materials of fine atomized aluminum powders and TiB₂ particles.Results show that the Al₂O₃/TiB₂/Al composites exhibit a yield strength of 258.7 MPa and an ultimate tensile strength of 279.3 MPa at 25℃due to the comprehensive strengthening effect of TiB₂ and Al₂O₃ particles.The strengthening effect of TiB₂ particles significantly weakens with rising the temperature to 350℃,and the Orowan strengthening mechanism between nano-Al₂O₃ and dislocation makes the yield strength and tensile strength of the composite material reach 98.2 and 122.5 MPa,respectively.After annealing at 350℃for 1000 h,due to the pinning effect of nano-Al₂O₃ at grain boundaries,the grains growth is suppressed significantly,and the strength and hardness do not decrease significantly.