Construction of Evaluation system of X-ray Stress Constants and Residual Stress for Alloys

Abstract

Ti alloy and Co-Cr alloy are authorized as implant materials. These alloys are utilized by machining and heat treatment. The manufacturing process will generate residual stresses that influence in destruction and deformation of materials. X-Ray Diffraction (XRD) is one of methods to estimate residual stresses. However, X-ray stress constants K of some alloys have never been reported before. So when residual stresses of some alloys are measured, stress constants of pure metal are used. This case isn’t clear for evaluation of residual stresses. In this study, system to measure X-ray stress constants of alloys were constructed. Specifically, we designed and fabricated a measurement system that can irradiate X-ray to materials under load. It was confirmed that the load was uniformly applied to the test piece. So the result of loading test showed that it is possible to use this apparatus. Next, we thought about a test piece for measuring residual stress with stress constants calculated by the constructed system. Vacuum annealing was performed on the pure titanium powder and the procedure for producing test pieces in a stress-free (strained) state was confirmed.