Abstract: In this work, the influence of microporosity on the tensile properties was investigated. The function relation between the microporosity index and mechanical properties was obtained. With the microporosity index increasing, both tensile strength and elongation decrease with/without HIP treatment. However, after SHT treatment, Laves phases and larger carbides still remain in the castings. They not only reduce the tensile strength of the castings, but also weaken the influence of the microporosity index on the tensile properties. In detail, the correlation coefficient of the SHT sample is obviously less than the correlation coefficient of the HIP+SHT sample, and the correlation coefficient of HIP + SHT sample is close to 1. SEM analysis show that crack initiation and expansion along microporosity is the main fracture mechanism of the SHT sample. In terms of HIP+SHT sample, the fracture mechanism is the reopening of the closed microporosity perpendicular to the direction of loading.
Authors: Maodong Kang, Yun Wu, Yahui Liu, Junwei Yu, Jun Wang, and Haiyan Gao
Keywords: K4169 alloy, HIP treatment, Microporosity, Properties