磁场对TIG焊接快速成形GH4169合金的组织及性能的影响

Effect of Electromagnetic Field on Microstructure and Mechanical Property of GH4169 Superalloy Fabricated by TIG Welding Rapid Forming

为改善TIG焊接快速成形GH4169合金的组织及力学性能,将电磁搅拌与TIG焊接快速成形结合,进行了不同磁场电流下GH4169合金的TIG焊接快速成形,分析了电磁场对沉积态GH4169合金组织、显微硬度及拉伸性能的影响。显微分析表明,电磁搅拌TIG焊接快速成形GH4169合金具有沿基材外延连续生长的特点,层与层之间过渡不明显,组织致密,无明显冶金缺陷;在一定磁场电流范围内,随磁场电流的增加,沉积态GH4169合金组织中枝晶间的共晶Laves相体积分数呈减少趋势;显微硬度测试表明,合金中枝晶间脆性Laves相的减少使沉积态试样组织均匀性获得一定的提高,试样的显微硬度从无磁场时的HV 232提高到磁场电流为1.0 A时的HV 253;室温下拉伸性能测试结果表明,施加适当电磁搅拌后合金的抗拉强度从无磁场时的550 MPa提高到磁场电流为0.5 A时的660 MPa,当磁场电流增大到9.0 A时抗拉强度下降,为520 MPa。

To improve the microstructure and mechanical property of TIG welding rapid forming GH4169 superalloy samples,electromagnetic stirring was combined to WRF and samples were fabricated with different magnetic field strengths. The effect of magnetic field current on microstructure,hardness and tensile property was investigated experimentally. Microstructure observation shows that continuous epitaxial growth of columnar grains is the typical characteristic of WRFed GH4169 superalloy,and no obvious metallurgical defect is found. Within certain rang of magnetic field strength,the amount of Laves phase decreases along with the increase of magnetic field current,which leading to the enhancement of microhardness through the improvement of homogeneity ofmicrostructure,for example,the microhardness increased from HV 232 to HV 253 when magnetic field current changed from 0 A to1. 0 A. Tensile testing at room temperature shows a better ultimate tensile strength of 660 MPa for a higher magnetic field current of0. 5 A; however,it decreased to 520 MPa when a too much higher magnetic field current of 9. 0 A is used.