热挤压对硼化物增强Mg-Li基复合材料组织与力学性能的影响  

Effect of hot extrusion on microstructure and mechanical properties of Mg-Li based composite materials reinforced by boron compound

作　　者：董奇夺[1] 刘志坚[1] 梁茜[1] 陶玉强[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《粉末冶金材料科学与工程》2014年第1期60-65,共6页Materials Science and Engineering of Powder Metallurgy

摘　　要：利用金相显微镜和扫描电镜观察铸态与热挤压态B4C增强Mg-Li基复合材料及其断口的显微形貌，研究热挤压对该复合材料组织和力学性能的影响。结果表明：热挤压加工可有效改善铸态Mg-Li基复合材料中强化相的分布均匀性，显著提高材料的屈服强度、抗拉强度和伸长率；基体合金在热挤压过程中发生动态再结晶，显微组织得到细化；在150～250℃范围内，挤压温度越高，强化相分布越均匀，基体合金的再结晶程度越高，因而复合材料的伸长率越高；200℃下热挤压的复合材料具有较好的力学性能，其抗拉强度为237.5 MPa，伸长率为21.7%，分别比铸态样品提高46.1%和126%。The effect of hot extrusion on the microstructure and mechanical properties of Mg-Li based composite materials reinforced by boron compound was investigated, through comparing the micromorphologies of the composites before and after hot extrution using optical microscopy and scanning electron microscopy. The results show that hot extrusion can effectively improve the uniformity of the distribution of strengthening phase. Yield strength, tensile strength and elongation of the extruded composite material are significantly increased compared with that of the ingot. Recrystallization in matrix alloy is observed and the microstructure is refined after hot extrusion. The degree of recrystallization and the value of elongation increase with increasing extrusion temperature in the range of 150~250 ℃. And the higher the extrusion temperature is, the better distribution of strengthening phase can be obtained. Additionally, the yield strength and the tensile strength of the composite material extruded at 200 ＆#176;C are higher than that of the composites extruded at 150 ℃ and 250 ℃, its tensile strength is 237.5 MPa and the elongation is 21.7%, which are 46.1%and 126%higher than that of the ingot sample, respectively.

关 键 词：热挤压 Mg-Li基复合材料 显微组织 力学性能 

分 类 号：TG376.1[金属学及工艺—金属压力加工]