A physically-based structure-property model for additively manufactured Ti-6Al-4V

Abstract

A physically-based, mixed-phase structure-property model is presented for microstructure-sensitivity of tensile stress-strain response, including yield stress, ultimate tensile strength, uniform elongation and flow stress (strain hardening), for additively manufactured Ti-6Al-4V. The interdependent effects of solutes, grain size, phase volume fraction and dislocation density are explicitly included. Solid-state phase transformation and dislocation density evolution are incorporated to simulate the effects of martensite dissolution and α-β transformation at high temperature. Predictions are validated by comparison with measured tensile test data for (i) effects of additive manufacturing process conditions (such as build orientation and sample size) on tensile properties, based on the microstructure attributes inherited from the process, and (ii) the effect of temperature on tensile stress-strain response across a broad range of temperatures. The model is thus applicable for rapid process-structure-property prediction, in conjunction with AM process modelling, to capture the effects of key manufacturing variables and for process optimization.

Keywords

• Additive manufacturing
• Microstructure
• Tensile properties
• Phase transformation
• Dislocation density