喷丸对宽间隙钎焊接头界面元素扩散及性能影响

Influence of Shot Peening on the Elemental Diffusion and Properties of Wide-Gap Brazed Joints

摘要:

基于Hastelloy X表面喷丸处理，研究喷丸对宽间隙钎焊接头界面元素扩散及性能的影响。对比了Hastelloy X表面未经喷丸处理及经过弹丸尺寸分别为0.180、0.300、0.500 mm喷丸处理后获得的宽间隙钎焊接头的微观组织和力学性能，利用SEM、EDS分析扩散层组织和元素分布特征。结果表明，喷丸处理产生的晶粒细化作用促进了降熔元素Si在Hastelloy X中的扩散，当弹丸尺寸为0.300 mm时，Si原子在钎焊接头组织中的扩散系数最大，为1.83×10^-8 mm²·s^-1，并且该钎焊接头的扩散层厚度最厚，为224.97 μm，其界面抗剪强度最大，为543.38 MPa，与未喷丸试样相比提高了19.39%。此外，通过理论计算得到了3种喷丸工艺下不同晶粒尺寸对Si元素扩散系数的影响，结合理论计算和实验数据，阐明了Si在宽间隙钎焊接头组织中的扩散机制。

Abstract:

Based on the surface shot peening treatment of Hastelloy X, this study investigated the impact of shot peening on the interfacial element diffusion and properties of wide-gap brazing joints. The microstructure and mechanical properties of wide-gap brazing joints obtained from Hastelloy X surfaces without shot peening and those treated with shot peening using ball sizes of 0.180, 0.300, and 0.500 mm were compared. SEM and EDS were used to analyze the diffusion layer structure and element distribution characteristics. The results indicate that the grain refinement effect from shot peening strengthening treatment promotes the diffusion of the melting-reducing element Si in Hastelloy X. When the shot size is 0.300 mm, the diffusion coefficient of Si in the brazing joint structure is the highest of 1.83×10^-8 mm²·s^-1; at this time, the diffusion layer is the thickest of 224.97 μm in thickness; the interface shear strength of the wide-gap brazing joint is the greatest of 543.38 MPa, which shows a 19.39% increase compared to that of the non-shot-peened sample. Additionally, theoretical calculations were conducted to determine the impact of different grain sizes under three shot peening processes on the diffusion coefficient of Si element. Theoretical calculations are combined with experimental data to elucidate the diffusion mechanism of Si in the microstructure of wide-gap brazing joints.