Effect of Bonding Conditions on the Mechanical Properties of Joint at the Elevated Temperature

Transient Liquid Phase Bonding of HP Alloy (Report 1)

Abstract

Transient liquid phase (TLP) bonding of HP alloy was investigated employing the insert metal MBF-50. TLP-bonding was carried out at 1423-1463 K for 600s in vacuum, Ar or N₂ atmosphere. Microconstituents such as Cr₇ (C, B)₃ were formed in the bonded layer. The amount of microconstituents decreased linearly with increasing the bonding temperature, and the microconstituents disappeared at the bonding temperature of 1463 K. The tensile properties of joint at 1273 K was improved with the bonding temperature in the range of 1423-1458 K indicating the maximum value almost same as those of the base metal at 1458 K, while the tensile properties fell down contrarily at 1463 K. The fracture of the joints bonded at 1458 K occurred in the base metal. The effects of the atmosphere on mechanical properties of joint at 1273 K were also examined. The tensile properties of joints bonded at 1458 K in Ar or N₂ atmosphere were the same level as those in vacuum atmosphere. The creep rupture strength of joints bonded at 1458 K in N₂ atmosphere reached nearly the minimum value of the base metal.