Abstract
Nowadays, selective laser melting (SLM) represents an option for manufacturing parts from titanium alloys, especially from Ti-6Al-4V alloy. However, mechanical properties of parts made of Ti-6Al-4V such as ductility and fatigue resistance are significantly lower than that for conventional manufactured parts. One of the promising ways to improve mechanical properties of SLM parts can be the use of deformation post-processing, for example, combining SLM with subsequent die forging. Therefore, the aim of the present study is to investigate the rheological properties and microstructure evolution of Ti-6Al-4V titanium alloy fabricated by SLM under temperatures of cold and hot deformation. The tests of cylindrical samples made of Ti-6Al-4V alloy was performed using a plastometer in the temperature range of 20–1200 °C, at strain rate ξ of 1 s− 1 up to strain e of 0.85. To evaluate the effect of manufacturing method of samples on flow behaviour and microstructure evolution of the material, the samples made of Ti-6Al-4V alloy fabricated by conventional technology were tested under the same conditions. The differences in the flow behaviour of SLM and conventional manufactured samples from Ti-6Al-4V which were significant at test temperatures of 20–900 °С were analysed and explained. In contrast to conventional manufactured parts, SLM-produced Ti-6Al-4V reveal higher peak stresses in the flow curves and temperature sensitivity of flow stresses. This in turn leads to high inhomogeneity of deformation of SLM-produced parts.
Correlation between Flow Behavior and Microstructure Evolution during α/β Deformation of TA19 Titanium Alloy**
