Deformation Characteristics of Inclusions in Powder Metallurgy Superalloy and Effects on Flaw Detection Signals

Author of the article:ZHOU Xiaoming, WANG Zhibiao, WANG Chaoyuan, QUAN Peng, ZENG Weihu, FENG Yefei

Author's Workplace：Science and Technology on Advanced High Temperature Structural Materials Laboratory, Beijing Institute of Aeronautical Materials, Beijing 100095, China

Key Words：powder metallurgy superalloy; non-metallic inclusions; deformation characteristics; ultrasonic signals

Abstract：The genetic characteristics of the shape and size of chemically stable ceramic inclusions in powdered superalloy were studied by artificial implantation of Al2O3 particles during sample preparation process, and the influence of ceramic inclusions on the identification of flaw detection signals was studied. The results show that the shape and size of Al2O3 particles do not change after hot isostatic pressing densification, and there is no reaction transition zone between Al2O3 particles and matrix. After hot extrusion deformation, Al2O3 particles are broken and distributed in a ‘chain-like’ distribution along the extrusion deformation direction, and the length of the ‘chain-like’ inclusions increases to about 2 to 5 times of the original size. After isothermal forging, the secondary crushing effect of the fine particles in the ‘chain’ inclusions is not significant, and they are inclined and dispersed with the flow of the matrix alloy. The deformation characteristics of the inclusion above indicate that the inclusion particles within a moderate deformation range are easier to be recognized by the flaw detection signal. The distribution characteristics of the flaw detection signal of the actual forging confirm the rationality of the test results.