Material characterization of Ti6Al4V alloy additively manufactured using selective laser melting technique

Selective laser melting (SLM) of titanium (Ti) alloys has been a focus of research in aerospace industries recently, due to ease of production, producing complex geometries and shorter production time as compared to conventional machining. Although some basic research on mechanical properties at room temperature is found in literature, the need for high-temperature applications, correlated with material characterization is inevitable. This work provides a benchmark for high-temperature mechanical and thermal properties of SLM manufactured Ti6Al4V alloy, formulated as a result of extensive experimentation in the form various mechanical and thermal tests. The Ultimate Tensile Strength (UTS) and Yield Strength (YS) of test specimens at 600 °C reduced to approximately 64% of those at room temperature (RT), whereas an increase in the percentage elongation from 9.6% to 15% at 600 °C, which is the usual trend in materials at elevated temperatures. Fracture toughness of 89.44 MPa m 1/2 was calculated from 3-point bend test. Hardness value of 37 HRC was measured on the Rockwell-C scale. Thermal conductivity and coefficient of thermal expansion increased from 2.11 W/m. K at RT to 3.73 W/m. K at 300 °C and 8 μm\m-⁰C at RT to 10 μm\m-⁰C at 600 °C respectively. Specific heat capacity values increased from 760 J/kg ⁰C to 925 J/kg ⁰C up to 200 °C, but decreased at higher temperatures from 200 °C to 600 °C. To the author's knowledge, for the first time comprehensive mechanical testing characterized the behavior of the developed material for its application in structures subjected to elevated temperatures.