激光快速成形TA15钛合金氩弧焊接头组织及力学性能
Microstructure and mechanical properties of MIG welded joint of laser melting deposited TA15 titanium alloy
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摘要: 对激光快速成形TA15钛合金与轧制TA15钛合金薄板进行了氩弧焊接试验,观察分析了焊接接头各区域组织特征,测试了焊接接头各区域的显微硬度以及室温拉伸性能.结果表明,激光快速成形件与轧制薄板氩弧焊焊缝凝固组织是具有粗大片状α+β组织特征外延定向生长的柱状晶.轧制件对焊接热影响敏感性强,热影响区晶粒发生严重长大现象,激光成形件靠近焊缝热影响区晶粒转变为等轴晶,距焊缝较远的热影响区仍保持柱状晶.激光成形件热影响区硬度最高,焊缝区及轧制件热影响区的硬度最低.焊接接头抗拉强度低于母材,塑性与轧制件相当,断裂位置位于轧制件热影响区.Abstract: Laser melting deposited (LMD) TA15 and rolled TA15 were welded by argon arc welding.The microstructure and phase constitution of the welded joint were studied by optical microscopy and scanning electron microscopy.The microhardness and mechanical properties of the welded joint were tested.The results indicate that the weld zone (WZ) mainly consists of columnar crystals with thick lamellar structure which epitaxially grow from the substrates.The grains in heat affected zone (HAZ) of rolled TA15 grow seriously because of its sensitivity to heat.The columnar grains in HAZ near weld zone of LMD TA15 turn into equiaxial grains.The microhardness of HAZ of LMD TA15 is the highest,while the WZ and HAZ of rolled TA15 is the lowest.The tensile strength of the welded joint is lower than that of both base metals,but the plasticity corresponds to the rolled TA15.Fracture position locates in the HAZ of rolled TA15.
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Key words:
- titanium alloy /
- laser melting deposition /
- argon- arc welding /
- microstructure /
- mechanical properties
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