Residual Stress in SLM Ti6Al4V Alloy Specimens

Abstract:

Selective Laser Melting (SLM) presents a modern manufacturing process with an innovative technology which allows the production of full-density objects or fine-structured parts with complex geometry and inner structures. Stability and certification of the properties of SLM parts are important tasks for all producers and end-users. One of the drawbacks of this technology is high residual stress in as-made SLM objects. In this study X-ray diffraction technique was used for investigating the residual stress induced into SLM Ti6Al4V alloy samples. Principal stresses were estimated for the cut rectangular specimen. Two types of the cantilevers were produced and numerical simulation of the stress was performed. The bending of cut cantilevers was measured before and after heat treatment. Next series of the samples had rectangular shapes and different thicknesses from 1 to 46 layers. All as-manufactured specimens attached to the substrate showed the presence of tensile residual stresses near the top surface. Residual stress along the laser scanning direction had magnitudes twice that of the stress in the perpendicular direction. Conclusions regarding directions and values of stresses in SLM objects from Ti6Al4V powder are given.

• Periodical: Materials Science Forum (Volumes 828-829)
• Pages: 305-310
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.828-829.305
• Online since: August 2015
• Authors: Ina Yadroitsava, Stephen Grewar, Daniel Hattingh, Igor Yadroitsev*
• Keywords: Numerical Simulations, Residual Stress, Selective Laser Melting, Titanium Alloy

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