烧结工艺及热挤压对纳米Al2O3p/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 Microstructure and properties of Nano-Al2O3 / 7075 Aluminum Matrix Composites

摘要:

采用粉末冶金与热挤压工艺制备了 10 wt%纳米Al₂O_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、硬度和压缩强度的影响。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降低,整体相对基体材料硬度均明显提高；复合材料经过挤压过后材料的致密度均在98 %以上；挤压比4:1,烧结温度为620℃、630 ℃、640℃时,相对于基体复合材料抗压强度分别提高了15.3%,17.2%,14.0%,随温度先增大后降低；挤压比8:1时,相对基体复合材料抗压强度分别提高了33.2%,34.1%,31.1%,强度随温度先增大后降低。而构型复合材料综上实验中弹性模量变化不大。

Abstract:

10 wt% Nano-Al2O3 / 7075 aluminum matrix composites were prepared by powder metallurgy and hot extrusion. The effects of sintering temperature and extrusion ratio on microstructure, 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 ratio 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 compactness of the composites after extrusion is 4:1, the sintering temperature is 620 ℃, 630 ℃ When the extrusion ratio is 8:1, the compressive strength of the composite increases by 33.2%, 34.1% and 31.1%, which increases first and then decreases with temperature. In conclusion, the elastic modulus of the composites has little change.