热挤压及时效对Mg-Zn-Si-Ca镁合金显微组织和力学性能的影响  

Effects of Hot Extrusion and Aging on Microstructure and Mechanical Properties of Mg-Zn-Si-Ca Magnesium Alloy

作　　者：汪洋[1] 张修庆[1] 陈舸[1] 韩敏玉[1] 

机构地区：[1]华东理工大学机械与动力工程学院承压系统与安全教育部重点实验室,上海200237

出　　处：《热加工工艺》2013年第8期163-166,170,共5页Hot Working Technology

基　　金：上海市自然科学基金资助项目(12ZR1407400)

摘　　要：为了提高镁合金的塑性变形能力,促进镁合金的应用,对均匀化退火后的Mg-6Zn-Si-0.25Ca镁合金进行热挤压及随后的时效处理,研究了热挤压过程中挤压工艺参数对材料显微组织与力学性能的影响。结果表明,Mg-6Zn-Si-0.25Ca镁合金热挤压时发生了动态再结晶,晶粒显著细化,力学性能大幅提高。挤压后的合金晶粒内部出现大量孪晶组织,随挤压温度升高,孪晶组织减少。时效处理可以进一步提高合金的力学性能。在挤压比为10时,合金经320℃挤压及190℃×8 h时效处理后,Mg-6Zn-Si-0.25Ca镁合金抗拉强度达到385 MPa,伸长率可达到11%。Homogenized Mg-6Zn-Si-0.25Ca magnesium alloy was hot-extruded and aging treated for improving the plastic deformation ability and promoting applications of magnesium alloys. In the hot extrusion process, the influences of extrusion parameters on the microstructure and mechanical properties of Mg-6Zn-Si-0.25Ca magnesium alloy were investigated. The results show that dynamic recrystallization occurs during hot extrusion. Compared with as-cast alloy, the grains are fine remarkably, and the mechanical properties are enhanced observably. Many twin crystals appeares in grains after hot extrusion, with the increase of extrusion temperature, twin crystal structures reduce. Aging further increases the mechanical properties of the alloy. The ultimate tensile strength of Mg-6Zn-Si-0.25Ca alloy extruded at 320 ℃ （extrusion ratio is 10） and aged at 190 ℃ for 8h is about 385MPa and the elongation is about 11%.

关 键 词：镁合金 热挤压 时效 力学性能 

分 类 号：TG156.96[金属学及工艺—热处理]