Mechanical behavior and fracture characteristics of simultaneously tensile loaded and laser heated Ti6Al4V alloy

Abstract

The mechanical behavior and fracture characteristics of simultaneously tensile loaded and laser heated Ti6Al4V alloy are investigated. Aiming at a comprehensive damage evolution and failure properties, a wide range of laser power densities and preload levels are considered. Stress-strain flow curve, temperature evolution, deformation degree and type, and corresponding mechanisms are explored in detail. The presented results demonstrate that temperature has a significant effect on the flow behavior of the material. The strength of the material and resistance to plastic flow decreased rapidly with the increase of laser power density. The remarkable reduction in failure time with the increase of either laser power density or preload is found. However, for higher preloaded states, there is the relatively smaller impact of laser power density on failure time. The metallographic analysis revealed that fracture characterizing features for Ti6Al4V alloy mainly comprises on micro-void nucleation, growth, and coalescence. Most of the fracture surfaces exhibited dimples and veins which indicates a ductile failure mode. With the increase of laser power density, dimples rupture is the predominant failure mode. While with the increase of preloading value, relatively more in-depth deformation effects and melting features were observed. On a macroscopic level, specimens experienced fracture after following the necking phenomenon. Temperature evolution history during the specimen exposure to combined tensile load and laser heating is providing a variety of information like phase change and melting etc. In addition, temperature profiles depict superheating of exposed surfaces to a temperature level notably beyond the melting temperature of the Ti6Al4V material.