Estimates of the mechanical properties of laser powder bed fusion Ti-6Al-4V parts using finite element models

Abstract

While significant progress has been made in the last few years, the structural integrity and reliability of Additively Manufactured (AM) parts is often questionable and inconsistent due to manufacturing defects, subpar strength, and low fatigue lives. Parallel work by the authors presented a generic simulation framework to predict metallurgical properties of AM parts. The framework was tested in one-element simulations of two alloys, and was applied to simulate the Selective Laser Melting (SLM) process of Ti-6Al-4V samples. In this work, the resulting validated predictions for volume fractions of phases and thicknesses of lamellar structures are used as input into numerical models for mechanical properties predictions. Experimental work was conducted in order to validate numerical predictions of tensile tests on dogbone specimens in the as-built and heat-treated condition. Comparisons between experiments and numerical predictions suggest that such modelling techniques, with minimal calibration efforts, can be used to predict the strength behavior including softening beyond the uniform elongation limit. Keywords: AM process simulation, Powder bed fabrication, Mechanical properties, Validation, Finite elements, Selective laser melting