Study of the impact of treatment modes on hardness, deformability and microstructure of VT6 (Ti-6Al-4V) and VV751P (Ni-15Co-10Cr) alloy samples after selective laser sintering

Abstract

Selective laser sintering is an advanced method for obtaining sophisticated products and assembly permanent joints. This is particularly relevant for heat resistant alloys employed in aviation equipment. Heat treatment modes traditionally applied to the products are chosen in accordance with conditions of further product operation. In this paper there are given the results of experimental study of hardness, deformability and microstructure of samples after selective laser sintering of Ni-15Co-10Cr and Ti-6Al-4V alloy powders. It has been determined that Ni-15Co-10Cr alloy ageing increases the hardness and deformability of samples; these characteristics decrease if the ageing lasts for 9-19 hours. Annealing of Ti-6Al-4V alloy samples results in preserving original hardness. After complete annealing, the hardness of samples decreases from 32 ... 33HRC to 24 ... 26HRC. Microstructural studies showed that there are cracks between layers in the surface of Ti-6Al-4V alloy samples after sintering and not complete annealing. After full annealing, cracks' width and length decreased. Cracks in Ni-15Co-10Cr alloy samples' microstructure were not detected.