高Al、Hf含量对Ni_3Al基合金激光焊接性能的影响  

Effects of High Al and Hf Content on Weldability of Ni_3Al Based Alloy by Laser Welding

作　　者：高海芸[1,2] 何润[3] 张冬云[2] 鹿堃[2] 

机构地区：[1]皖西学院材料与化工学院,安徽六安237012 [2]北京工业大学激光工程研究院,北京100022 [3]皖西学院机械与电子工程学院,安徽六安237012

出　　处：《中国表面工程》2015年第2期90-100,共11页China Surface Engineering

基　　金：六安市定向委托皖西学院市级研究项目(2013LW015)

摘　　要：为了研究高Al、Hf含量对Ni3Al基合金焊接性能的影响,采用激光焊接3种成分合金,分析焊缝凝固机理,并对比所得裂纹敏感性,同时从预热温度、激光光源性质等方面研究激光焊接工艺。Al元素成分增加,使合金降低了焊缝裂纹中偏析较严重的Mo元素含量,并使凝固过程的脆性温度范围减小,离共晶区较远,致使凝固组织(γ+γ′)共晶相减少。Hf元素含量增加使枝晶间得到良好的填充,使其相变成细密羽毛状(γ+γ′)共晶体,明显降低合金的裂纹敏感性。通过调节母材预热温度,激光波长,在冷却速度较快时能够在一定程度上降低裂纹的敏感性,但仍未完全消除裂纹。而采用波长较短、光斑面积较大的半导体激光焊接得到无裂纹焊缝。Influence of high Al and Hf content on the laser welding properties of Ni3Al base alloy was investigated. Three types of alloys with different compositions were used to analyze the weld solidification mechanism and the crack sensitivity. The laser welding process was studied from such parameters as preheating temperature, laser source properties, etc. It is found that with the increase of Al centent, the segregation of Mo content in the weld crack was reduced, and the brittle temperature range got smaller during the solidification process to result in a decrease of the solidified structure （γ＋γ′） eutectic phases in the remote eutectie area. Meanwhile, with the increase of Hf element content, the crack sensitivity was reduced by a fine plume （γ＋γ′） eutectic was generated from good interdendritic filling. Therefore, the crack sensitivity could be reduced to some extent by adjusting the preheating temperature and laser wavelength due to the high cooling speed, however, some small cracks still existed, which would disappear if welding with semiconductor laster of shorter wavelength and larger spot is used.

关 键 词：激光加工 NI3AL基合金 金属间化合物 裂纹 

分 类 号：TG174.44[金属学及工艺—金属表面处理] TG113.263[金属学及工艺—金属学]