烧结工艺及热挤压对纳米Al_(2)O_(3p)/7075铝基构型复合材料组织与性能的影响

Effects of Sintering Process and Hot Extrusion on Microstructures and Properties of Nano-Al_(2)O_(3p)/7075 Aluminum Matrix Composites

采用粉末冶金与热挤压工艺制备了Al_(2)O_(3)质量分数为10%的纳米Al_(2)O_(3p)/7075铝基构型复合材料。研究了真空与非真空下不同烧结温度、不同挤压比对复合材料微观组织、致密度、弹性模量、硬度和抗压强度的影响。结果表明:随烧结温度升高,挤压比4:1与8:1构型复合材料的硬度皆为先增加后减小,整体硬度相对基体材料均明显提高。复合材料经过挤压后的致密度均在98%以上。挤压比4:1,烧结温度为620、630、640℃时,相对于基体材料抗压强度分别提高15.3%,17.2%,14.0%,随温度升高先增大后减小。挤压比8:1时,相对于基体材料抗压强度分别提高33.2%,34.1%,31.1%,随温度升高也呈现先增大后减小。而构型复合材料的弹性模量变化不大。

10wt%nano-Al_(2)O_(3p)/7075 aluminum matrix composites were prepared by powder metallurgy and hot extrusion.The effects of sintering temperature and extrusion ratio on microstructure,relative density,elastic modulus,hardness and compressive strength of the composites were studied.The results show that with the increase of sintering temperature,the hardness of the composites with extrusion ratios of 4:1 and 8:1 increases at first and then decreases,and the overall hardness of the composites increases obviously.The compactness of the composites after extrusion is more than 98%.The compressive strength of the composites with extrusion ratio of 4:1,the sintering temperatures of 620,630,640℃,increases by 15.3%,17.2%,14.0%compared to matrix,respectively.When the extrusion ratio is 8:1,the compressive strength of the composites increases by 33.2%,34.1%and 31.1%,which increases at first and then decreases with increasing temperature.In conclusion,the elastic modulus of the composites has little change.