Abstract
A study was undertaken on the compressive high strain rate properties and deformation behaviour of Direct Metal Laser-Sintered (DMLS) Ti6Al4V (ELI) parts in two separate forms: as-built (AB) and stress relieved (SR). The high strain rate compression tests were carried out using a Split Hopkinson Pressure Bar test system at ambient temperature. The average plastic strain rates attained by the system were 400 s−1 and 700 s−1. Comparative analyses of the performance (flow stresses and fracture strains) of AB and SR specimens were carried out based on the results obtained at these two plastic strain rates. Microstructural analyses were performed to study the failure mechanisms of the deformed specimens and fracture surfaces. Vickers microhardness test values were obtained before and after high strain rate compression testing. The results obtained in both cases showed the strain rate sensitivity of the stress-relieved samples to be higher in comparison to those of as-built ones, at the same value of true strain.
Highlights
Direct metal laser sintering (DMLS) is a technology that has been available commercially since1995
Peng et al [16] paid special attention to both the effects of strain rate as well as temperature on the tensile and compressive plastic flow and fracture characteristics of Ti6Al4V alloy produced via 3D laser deposition technology
The optical microstructural microstructural observations observationsof of the the longitudinal longitudinal sections sectionsof of the the two two forms forms of the alloy shown in Figure 4, revealed revealed prior prior β-grains β-grains elongated approximately parallel to the build direction, before and after after stress-relieving stress-relieving heat heat treatment
Summary
Direct metal laser sintering (DMLS) is a technology that has been available commercially since. Peng et al [16] paid special attention to both the effects of strain rate as well as temperature on the tensile and compressive plastic flow and fracture characteristics of Ti6Al4V alloy produced via 3D laser deposition technology. The layer-by-layer building process of metal powder in the DMLS process with non-optimal parameters influences the porosity, whereas rapid cooling influences the formation of the resulting microstructure Together, these two factors determine the mechanical properties of the part produced. The aim of the work reported on in this paper was to develop an understanding of the mechanical behaviour of DMLS-fabricated Ti6Al4V (ELI) parts under high strain rate compressive loading using a. The variations of microhardness, stress–strain behaviour and microstructural characteristics of the two forms of alloy under high strain rate compressive loading were studied in this work, and are reported here
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