The Joint Properties of A564-630 Stainless Steel Made by Transient Liquid Phase Bonding: Microstructural and Mechanical Strength Evaluation

Nickel-based filler alloy with a liquidus temperature of 1024 degrees C was used for transient liquid phase (TLP) bonding of A564-630 martensitic precipitation hardening stainless steel. TLP experiments were carried out at a constant temperature of 1050 degrees C for different times between 30 to 90 min employing 75 mu m thick filler metal to achieve the best TLP parameters. A Ni coating of 10 mu m was coated to the base materials to compare the joints with and without coating. The effect of bonding conditions on the microstructure and mechanical properties of samples was investigated. The isothermal solidification was achieved after 60 min of bonding time. The results showed that bond shear strength increased with increasing the TLP time. The Ni coating improved the microstructure and shear strength of the joint and the Ni-coated base metal TLP bonded at 1050 degrees C for 90 min showed lap-shear strength of maximum 461 MPa. By comparing the results of the line scan analysis and the hardness profile, it is concluded that with increasing the TLP time, a more uniform distribution of alloying elements and hardness profile across the joint region was achieved.