Heat treatment simulation of Ti-6Al-4V parts produced by selective laser melting

The present work focuses on the simulation of the heat treatment applied after printing of Ti-6Al-4V parts. The numerical tool aims at predicting the influence of heat treatment conditions (e.g. holding time, temperature) on the residual stress field and the distortions for SLM produced parts. The numerical model relies on a thermo-viscoplastic constitutive model. To determine the corresponding material parameters, different creep tests have been performed at temperatures ranging from 723 K to 1173 K. According to the results, the stationary creep strain rate is independent of the hydrostatic pressure, which indicates that the high temperature behavior is not impacted by the initial porosity. Also, the material parameters are observed to change significantly from 873 K, which is due to the progressive transformation of the initial martensitic alpha' microstructure into the alpha+beta lamellar microstructure. To validate the proposed approach, some numerical simulations have been performed for two different parts, for which distortions have been measured. The numerical and experimental distortions have then been compared to each other. For both parts, the agreement between experimental and numerical data is correct.

Automated summary

This study focuses on simulating the heat treatment of Ti-6Al-4V parts produced through SLM printing, aiming to predict the residual stress field and distortions. Different creep tests were conducted to determine material parameters, showing that high temperature behavior is not significantly affected by initial porosity and material parameters change notably above 873K due to microstructure transformation. Experimental and numerical distortions were compared, showing good agreement.