挤压比对AZ31B镁合金组织与力学性能的影响  

Influence of extrusion ratio on microstructure and mechanical properties of AZ31B magnesium alloy

作　　者：林涛[1] 刘运腾[1,2] 周吉学[1,3] 庄海华[1] 马百常 杨院生[4] 

机构地区：[1]山东省科学院新材料研究所,山东济南250014 [2]山东省轻质高强金属材料省级重点实验室(筹),山东济南250014 [3]山东省汽车轻量化镁合金材料工程技术研究中心,山东济南250014 [4]中国科学院金属研究所,辽宁沈阳110016

出　　处：《金属热处理》2017年第6期119-123,共5页Heat Treatment of Metals

基　　金：山东省科学院青年基金;山东省自然科学基金(ZR2015EQ019)

摘　　要：研究了不同挤压比对AZ31B镁合金显微组织、力学性能的影响。采用光学显微镜观察了显微组织,拉伸试验测试了力学性能,并配合扫描电镜观察了拉伸试样的断口形貌。结果表明:随着挤压比的增加,组织由部分动态再结晶转变为细致的完全动态再结晶,挤压比61~109时,晶粒细化程度变小;挤压比增加,强度及伸长率都增加,抗拉强度、屈服强度及伸长率最高分别达340 MPa、271.5 MPa和21.5%,但高挤压比所获得的性能提高收益小。合金拉伸断口由混合断裂转变为明显韧性断裂。合理控制挤压比可得到良好的综合性能与均匀细致的组织。Influence of extrusion ratio on microstructure and mechanical properties of AZ31 B magnesium alloy was studied. The microstructure was observed by means of optical microscopy（ OM）,the mechanical properties were examined by room-temperature tensile test and the tensile fracture morphology was observed by means of scanning electron microscopy（ SEM）. The results show that with extrusion ratio increasing,the microstructure of the alloy transform from partial dynamic recrystallization to complete dynamic recrystallization,and the microstructure is more homogeneous and finer. But the grain size declines a little when the extrusion ratio is increased from 61 to 109. With extrusion ratio increasing,both the strength and ductility are improved,and the maximum tensile strength,yield strength and elongation are340 MPa,271. 5 MPa and 21. 5%,respectively. But the mechanical properties of the extruded alloy are benefited a little under high extrusion ratio. The fracture mechanism of the alloy is transferred from mixed fracture mode to obvious ductility mode. Fine and homogeneous microstructure and good mechanical properties can be obtained by controlling the extrusion ratio during extrusion processing.

关 键 词：AZ31B镁合金 挤压比 显微组织 力学性能 

分 类 号：TG146[一般工业技术—材料科学与工程]