热挤压对YAl2p/Mg-14Li-3Al复合材料组织和性能的影响

利用搅拌铸造法制备出不同体积分数的YAl_(2p)/Mg-14Li-3Al复合材料,然后将其挤压成薄壁管材,通过金相显微镜、扫描电镜和万能试验机等手段研究了热挤压变形对复合材料显微组织及力学性能的影响。结果表明,通过热挤压变形,YAl_(2p)增强体的分散性得到改善,复合材料的显微组织明显细化,力学性能显著提升。其中挤压态体积分数为1%的YAl_(2p)/Mg-14Li-3Al复合材料与铸态相比,抗拉强度和屈服强度均提高了60%以上,塑性得到改善。在挤压的过程中,复合材料的挤压力峰值与Mg-14Li-3Al合金相比略有增加,且挤压力峰值达到的时间存在滞后的现象。

Effect of hot extrusion on structure and properties of YAl2p/Mg-14Li-3Al composites

YAl2p/Mg-14Li-3Al composites with different volume fraction were fabricated by stir casting,and then the as-cast ingots were extruded as composite thin-walled tubes with the defined experimental parameters.Effects of hot extrusion deformation on microstructure and mechanical properties of YAl2p/Mg-14Li-3Al composites were investigated by optical microscope,scanning electronic microscope,tensile tests and so on.The results show that hot extrusion deformation can effectively improve the YAl2p distribution and the mechanical properties of the composites.In addition,the grains of matrix are significantly refined after hot extrusion.For as-extruded YAl2p/Mg-14Li-3Al composites with volume fraction of 1％,compared with as-cast condition,the tensile strength and the yield strength are both improved by over 60％,and the ductility is improved.In the process of hot extrusion,the extrusion pressure peak of the composite is improved slightly compared with Mg-14Li-3Al alloy,and the time of the peak pressure of the composite lags behind the alloy.