Microstructure transformation and variant selection of SLM and SLM + HT formed TA17 alloy

In order to systematically investigate the microstructure transformation mechanism of selective laser melting(SLM) formed TA17 alloy, the microstructures of TA17 alloy were characterized and analyzed under SLM and SLM + heat treatment(HT). The results show that under extremely fast cooling conditions, the microstructure of TA17 is dominated by fine needle-shape α phase, with plate textures 0 0 0 1 < 1 0 −1 0 >, 1 0 −1 0 < 1 1 −2 0 > and 1 1 −2 0 < 1 0 −1 0 > as main types; and two types of variants, namely the 60°/1 1 −2 0 and 60.83°/−1.377 −1 2.377 0.359, are inclined to be generated. While after a treatment of 950 °C/2 h + air cooling, a dual state α structure is formed on the TA17 alloy with typical equiaxed grains and a plate-like morphology. With the increase in the degree of texture dispersion, the strength decreased significantly. There was also a change in variant selection, as the proportion of 60°/1 1 −2 0 and 60.83°/−1.377 −1 2.377 0.359 variants decreased significantly, 63.26°/−10 5 5 −3 become the major variant.