摘要
对42 mm厚A6N01S-T5铝合金型材进行双面搅拌摩擦焊接,焊后沿焊缝横截面将接头分为上、中、下三层分别进行疲劳试验,探究其疲劳性能;通过金相组织观察、显微硬度测试、断口分析等方法分析接头疲劳断裂的原因。结果表明,接头疲劳断裂多发生在热影响区,上、中、下三层的疲劳极限分别为103.9 MPa、101.4 MPa和102.2 MPa;焊核区微观组织为细小等轴晶粒,热影响区组织形貌与母材接近,略有粗化现象;接头显微硬度分布呈W型,母材硬度约为108 MPa,焊核区约为75 HV,距离焊缝中心约10 mm的HAZ软化区硬度值最低,约为55~60 HV;疲劳源多为氧化物夹杂造成的应力集中诱发形成。
Bi-friction stirring welding of 42 mm A6N01S-T5 aluminum alloy section is implemented.FSW joints are divided into upper,middle and lower layers along weld junction and the fatigue property of the joints is researched by fatigue test.The reasons of fatigue fracture of the joints are analyzed by microstructure observation,micro-hardness testing and fracture analysis.The result shows that fatigue fracture is occurred mostly in the heat-affected zone.The fatigue limit of FSW joints is 103.9 MPa,101.4 MPa and102.2 MPa.The microstructure of nugget zone is equiaxed grain and the heat-affected zone is slightly coarsening phenomenon.The micro-hardness of joints is W-shaped and the hardness of base material is about 108 HV.And nugget zone is about 75 HV.The minimum hardness value is occurred in softening zone which is 10 mm away from the weld center and is about 55~60 HV.The stress concentration caused by oxide inclusions induces the fatigue source.
出处
《电焊机》
2016年第3期66-70,共5页
Electric Welding Machine
