激光选区熔化成形YSZ/7075铝合金的显微组织与力学性能

Microstructure and mechanical properties of YSZ/7075 aluminum alloy by selective laser melting

摘要:

以7075铝合金粉末为原料，采用SLM技术制备了7075铝合金和YSZ/7075复合材料试样，并研究了SLM工艺参数及钇稳定氧化锆（YSZ）添加含量对7075铝合金试样微观组织结构和力学性能的影响．试验结果表明：SLM成形7075铝合金试样的相对密度，随着激光能量密度的增加呈先增大后减小的趋势；SLM成形试样沿晶界分布着网状裂纹，添加钇稳定氧化锆（YSZ）纳米粉体能明显抑制SLM成形7075铝合金的裂纹；当YSZ添加量为2%、激光功率为270 W、扫描速度为800 mm/s时，试样相对密度为96.62%，平均晶粒尺寸由20.4 μm细化至4.26 μm，显微硬度为120 HV，试样的抗拉强度及屈服强度分别为209 MPa和196 MPa，是未添加YSZ试样的5.5倍和2倍，延伸率为4%．

Abstract:

Using 7075 alloy powder as raw material， 7075 aluminum alloy and YSZ/7075 composite samples were fabricated by SLM. The effects of SLM process parameters and yttrium stabilized zirconia （YSZ） content on the microstructure and mechanical properties of 7075 aluminum alloy samples were studied. The test results show that the relative density of 7075 aluminum alloy samples formed by SLM， with the increase of laser energy density， it increases first and then decreases； moreover， there are network cracks along the grain boundary of SLM formed samples. The addition of yttrium stabilized zirconia （YSZ） nano powder can significantly inhibit the cracks of SLM formed 7075 aluminum alloy； when the addition of YSZ was 2%， the laser power was 270 W and the scanning speed was 800 mm/s， the relative density of the sample was 96.62% and the average grain size increased from 20.4 μm refined to 4.26 μm. The microhardness is 120 HV， the tensile strength and yield strength of the sample are 209 MPa and 196 MPa respectively， which are 5.5 times and 2 times that of the sample without YSZ， and the elongation is 4%．