摘要
对LZ91镁锂合金进行了搅拌摩擦改性加工,采用光学显微镜、拉伸试验机、显微硬度测试仪等设备对LZ91镁锂合金搅拌摩擦加工的表面形貌、金相组织、拉伸性能和显微硬度进行测试和分析。结果发现:当旋转速度为1800 r·min^(-1)、加工速度在30~100 mm/min时,LZ91镁锂合金加工表面成型良好,无明显缺陷,表面存在"起皮"现象,"起皮"程度随加工速度增大而变小。随加工速度的增加,搅拌摩擦加工焊核区晶粒呈现出逐渐变小的现象。α-Mg相和β-Li相在前进侧热机影响区的向上弯曲变形程度大于在后退侧的变形程度。相比前进侧热机影响区,后退侧热机影响区的α-Mg相晶粒显著细化,而β-Li相晶粒却明显粗化。加工速度在30~100 mm/min范围增大时,抗拉强度和焊核区的显微硬度先上升后下降,伸长率逐渐变大。当加工速度为60 mm/min时,抗拉强度达到最高值252 MPa。
Friction stir processing was carried out on LZ91 magnesium lithium alloy.The surface morphology,metallographic structure,tensile properties and microhardness of LZ91 magnesium lithium alloy were tested and analyzed by optical microscope,tensile testing machine,microhardness tester and other equipment.The results show that when the rotation speed is 1800 r·min^(-1) and the advancing speed is between 30-100 mm/min,the surface of LZ91 magnesium lithium alloy has a good appearance without obvious defects,and there is"peeling"phenomenon on the surface,and the degree of peeling decreases with the increase of advancing speed.With the increase of advancing speed,the grain size of the nuclear zone becomes smaller.The bending deformation ofα-Mg phase andβ-Li phase in the advancing side is greater than that in the retreating side.Compared with the advancing side,theα-Mg phase grains in the retreating side are significantly refined,whileβ-Li phase grains are significantly coarsened.The tensile strength and microhardness of nugget zone first increase and then decrease with the increase of advancing speed from 30 mm/min to 100 mm/min,and the elongation increases gradually.When the advancing speed is 60 mm/min,the tensile strength reaches the highest value of 252 MPa.
作者
刘刚
秦丽霞
张玺
彭银利
耿家源
LIU Gang;QIN Lixia;ZHANG Xi;PENG Yinli;GENG Jiayuan(School of Intelligent Manufacturing,Nanyang Institute of Technology,Nanyang 473000,China;Department of Educational Affairs of Nanyang Institute of Technology,Nanyang 473000;Yangtze University College of Technology&Engineering,Jingzhou 434020,China)
出处
《热加工工艺》
北大核心
2021年第18期56-60,共5页
Hot Working Technology
基金
国家自然科学基金项目(51701026)
湖北省自然科学基金项目(2019CFC909)
南阳理工学院博士科研启动项目(510109)
长江大学工程技术学院科研基金项目(2019KY03)。
关键词
LZ91镁锂合金
搅拌摩擦加工
加工速度
LZ91 magnesium lithium alloy
friction stir processing
advancing speed
