高压凝固Al2O3/Al-10Si复合材料组织热稳定性及力学性能研究

Effect of Heat Treatment on Thermal Stability of Microstructure and Mechanical Properties of High Pressure Solidified Al2O3/Al-10Si

摘要:

本文采用高压凝固的方法分别在3、4、5 GPa的压力下制备了Al₂O₃/Al-10Si复合材料,并分别在160 ℃保温2、4、6 h的条件下研究了高压凝固Al₂O₃/Al-10Si复合材料的组织热稳定性以及力学性能转变规律。研究表明：热处理导致高压凝固Al₂O₃/Al-10Si复合材料α相固溶的Si在热激活的作用下脱溶析出,聚集长大形成细小颗粒弥散分布于α相内,形成沉淀强化；160 ℃热处理后α相固溶的Si析出,过饱和程度下降,材料性能逐渐趋于稳定,在沉淀强化的共同作用下,Al₂O₃/Al-10Si复合材料抗压强度和压缩率较热处理前均有所上升。而160℃保温4 h的条件下,材料的综合力学性能最好。尤其在5 GPa压力下凝固的Al₂O₃/Al-10Si复合材料,抗压强度可达到716 MPa。

Abstract:

Al₂O₃/Al-10Si composites were prepared by high pressure solidification at 3, 4, 5 GPa, and then heat treated at 160 °C for 2, 4, and 6 h. Thermal stability of microstructure and mechanical properties of Al₂O₃/Al-10Si composites under high pressure were systematically studied. The results showed that heat treatment leads to the precipitation of Si particles due to the supersaturation in α phase.The precipitation of Si leads to a decrease of supersaturation. The compression strength and ration shows a slight increase after heat treatment due to the combination of precipitation strengthening and solid solution strengthening. At 160℃/4h, Al₂O₃/Al-10Si composites showed the best mechanical properties. After solidified under 5GPa and heat treatment at 160℃/4h, Al₂O₃/Al-10Si composites got the maximum compressive strength which is about 716MPa.