Effects of HIP on Microstructure and Mechanical Properties of K4536 Alloy Manufactured by SLM

Abstract

K4536 alloy formed by SLM was treated by HIP, and the effects of HIP on the microstructure and high-temperature mechanical properties were studied. The results show that the surface of sample manufactured by SLM has cracks, and the longitudinal and horizontal microstructures are different. After HIP processing, the cracks in the sample is repaired to some extent, the microstructure of the sample also is changed, and many second phase particles are dissolved out from the matrix. We know that the precipitation is M23C6 phase by TEM diffraction analysis. Furthermore, the surface of sample has “white bright layer” with the thickness of about 30 μm, the “white bright layer” is resulted by the decrease of Cr by EDS energy spectrum analysis. The K4536 alloy sample formed by SLM has different high-temperature tensile properties in the vertical and horizontal, and the vertical performance is better than that of horizontal. After HIP processing, the vertical and horizontal performances have little difference, and the high-temperature strength of the sample is reduced, the high-temperature plasticity is increased.

Keywords

• selective laser melting
• hot isostatic pressing
• K4536 alloy
• high-temperature performance