摘要
LZ91双相镁锂合金可通过搅拌摩擦加工方式实现组织细化及双相均匀化,搅拌摩擦加工中材料前进侧和后退侧流动性差异使两侧组织特征区别较大,力学性能不稳定。本研究采用光学显微镜(OM)、场发射扫描电子显微镜(SEM)、万能拉伸试验机,研究了退火处理对搅拌摩擦加工LZ91双相镁锂合金搅拌区微观组织及力学性能的影响。结果表明,不同特征的初始变形组织在热处理过程中的组织演变规律不同,双相分布均匀的细晶结构在热处理中稳定长大,前进侧与基体组织突变得到改善,逐渐由弱织构形成c-轴平行于PD方向的基面织构。后退侧团聚成岛状的α细晶在热处理中迅速长大,热稳定性较差。250℃下退火处理30 min后,搅拌摩擦加工LZ91镁锂合金均匀伸长率从5.8%提升至8.8%,拉伸中前进侧收缩率从0.2降低至0.1,应力集中得到有效改善,性能薄弱区域在退火处理前后均为后退侧组织。
Grains and phases in LZ91 dual-phase Mg-Li alloy could be refined and homogenized by friction stir processing(FSP).The effects of annealing treatment on the microstructure and mechanical properties of LZ91 dual-phase Mg-Li alloy processed by friction stirring were studied by optical microscopy(OM),scanning electron microscopy(SEM)and uniaxial tensile test.The results showed that initial microstructure characte-ristics affected organizational evolution.Uniform and small dual-phases could grow smoothly during heat treatment.Drastic organizational interface between stir zone and matrix was weakened during annealing treatment.Texture of fine grains in advancing side were increased slowly.Fine grains inα-islands grew fast in retreating side of samples.Uniform elongation of FSPed LZ91 increased from 5.8%to 8.8%after annealing treatment at 250℃for 30 min.Stress concentration was improved in advancing side of samples.Reduction of area decreased from 0.2 to 0.1.The stress concentration was improved effectively,and the weak area was retrograde before and after annealing treatment.
作者
江雯
蒋璐瑶
黄伟九
郭非
董海澎
JIANG Wen;JIANG Luyao;HUANG Weijiu;GUO Fei;DONG Haipeng(College of Materials Science and Engineering,Chongqing University of Technology,Chongqing 400054,China;Chongqing Key Laboratory of Mold Technology,Chongqing University of Technology,Chongqing 400054,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2020年第S01期307-311,共5页
Materials Reports
基金
重庆市自然科学基金(cstc2018jcyjAX0107,cstc2019jcyj-msxmX0111)
中国博士后基金(2018M643407)
重庆理工大学科研启动基金。
关键词
LZ91镁锂合金
搅拌摩擦加工
显微组织
力学性能
退火处理
LZ91 magnesium-lithium alloy
friction stir processing
microstructure
mechanical property
annealing treatment