Microstructure and Interfacial Reactions of Resistance Brazed Lap Joints between TC4 Titanium Alloy and 304 Stainless Steel Using Metal Powder Interlayers.

Pengxian Zhang,Zhizhong Fang,Shilong Li

doi:10.3390/ma14010180

Abstract

In the brazing joint between titanium alloy and stainless steel, a lot of Fe-Ti intermetallic compounds (IMCs) can be easily formed to make joints crack. A lap resistance brazing process with metal powder layers on both sides of the filler metal was used to solve this problem. The microstructure and metallurgical behavior of joints was studied through comparative experiments. The result showed that Nb, V and Cr powders and the solder reacted with the base material to form a new phase, which replaced the Ti-Fe brittle phase in the joint. At the same time, metal powder clusters hindered the diffusion of Ti and Fe elements and improved the distribution of new phases. The established atomic reaction model revealed the metallurgical behavior and formation mechanism of the joints. Therefore, the intervening position of the metal powder layer and the multi-reaction zone structure are the main reasons the shear strength of joints is improved.

Highlights

Introduction and304 Stainless Steel Using MetalThe group weldment of the titanium alloy and stainless steel can make full use of the advantages of these two materials and have good economic benefits simultaneously, so its high-quality joints have extensive application prospects in nuclear, petrochemical, transportation and aerospace industries [1,2,3]
A rational solder is usually chosen as the middle transition layer to block the formation of brittle intermetallic compounds (IMCs) at the titanium alloy/stainless steel interface
The results showed that the niobium middle layer effectively hindered the formation of Fe-Ti intermetallic compounds (IMCs) in the joint under reasonable welding parameters, and the shear strength of the joint was significantly improved

Summary

Introduction

Introduction and304 Stainless Steel Using MetalThe group weldment of the titanium alloy and stainless steel can make full use of the advantages of these two materials and have good economic benefits simultaneously, so its high-quality joints have extensive application prospects in nuclear, petrochemical, transportation and aerospace industries [1,2,3]. A rational solder is usually chosen as the middle transition layer to block the formation of brittle intermetallic compounds (IMCs) at the titanium alloy/stainless steel interface. Existing research indicates that welding the solid phase with the addition of an intermediate transition metal was an effective method to achieve a reliable connection between titanium alloy and stainless steel [4,8,9,10]. Parameters such as welding current, welding time and electrode pressure are important to consider in resistance spot welding.

Methods

Results

Conclusion