Selective laser melting and post-processing stages for enhancing the material behavior of cobalt-chromium alloy in total hip replacement: a review

Cobalt-chromium alloys and Ultra High Molecular Weight Polyethylene (UHMWPE) are widely used in total hip replacement due to their multifunctional properties such as high mechanical strength, hardness, fatigue, and tribological properties. The material has been more popular among researchers that pushing them to refine the multifunctional properties of materials by using different fabrication and post-processing methods. Recent studies found that the Selective Laser Melting (SLM) technique of additive manufacturing (AM) shows a major response in changing the properties over the traditional methods, but there exist few problems while printing the cobalt-chromium alloys in SLM. However, it is hard to use cobalt-chromium alloys directly in the human body without post-processing stages such as post-heat treatment, surface modification, and Osseo-integration stage because it helps to improve the durability, reduce the ion elements release, wear debris, and promotes more adhesive strength between the tissue and stems. This review article explores the effects of process parameters on the SLM printed product and analyzes the post-processing stages to enhance the properties of printed components for total hip replacement. Furthermore, the solution for the problems and future research work are adequately discussed for restricting the ion element leaching of Cobalt-Chromium alloys.