基于DIC的镍基焊材焊接接头局部力学性能研究

Research on local mechanical properties of Nickel-based welding joint based on digital image correlation

摘要:

本文通过显微组织分析、数字图像相关技术（DIC）试验以及硬度测试，系统研究了15CrMoR母材与镍基焊材焊接接头各区域的局部力学性能。基于DIC方法获取了镍基焊材焊接接头拉伸过程的全场应变云纹发现：焊缝区域应变较小且不均匀，母材区域应变量大，热影响区均匀过渡。在此基础上构建了焊接接头不同区域的局部应力应变曲线，并揭示了焊接接头局部力学性能参数的分布规律。由焊接接头显微组织的分析可知，局部力学性能参数的分布与显微组织的分布存在密切联系。最后，结合显微硬度与强度参量在焊接接头的分布规律，构建了两者的关联方程，便于镍基焊材焊接接头局部力学参数的估算。

Abstract:

In this paper, the local mechanical properties of the welding joint for 15CrMoR base metal and nickel based welding metal were systematically studied by means of microstructure analysis, digital image correlation (DIC) test and hardness test. Based on DIC method, the whole field strain nephogram was obtained for the welding joint of nickel based welding metal during tensile process. It was found that the strain in the welding area was small and inhomogeneous, but it was large in base metal area, while it was uniformly variated in the heat affected zone. Then, the local stress-strain curves of different regions for the welding joint were constructed, and the distribution of local mechanical properties parameters in the welding joint was revealed. Based on the microstructure analysis of welding joint, the distribution of local mechanical properties parameters was closely correlated to the distribution of microstructure. Finally, combining the distributions of microhardness and strength parameters in the welding joint, the correlation equations of them were established, which were convenient to estimate the local mechanical parameters for the welding joint of nickel based welding metal.