Selective laser melting of CoCr alloys in biomedical application: A review

Abstract

Additive manufacturing (AM) is used to describe the fabrication of functional, end use components in a layer-by-layer manner based upon a 3D design model. It enables the fabrication of complex geometries which are difficult to manufacture using alternative methods. The development in AM technology led to the creation of three typical processes in terms of laser sintering, laser melting and laser metal deposition. Among them, the selective laser melting (SLM) is the most in-demand approach, as its potential of rapid manufacturing of complex and unique parts have been demonstrated. Recently, cobalt-chromium (CoCr) alloys have gained a lot of interest in the research community due to their greater hardness, mechanical strengths, and biocompatibility. CoCr alloys are widely used in biomedical applications as they are the hardest known biocompatible alloy along with good tensile and fatigue properties. However, the fabrication processes for these alloys, such as casting, cutting, and plastic works, are usually difficult because of their high melting point, hardness, and limited ductility. Moreover, the method which is used to manufacture the alloy plays a very important role in the mechanical and metallurgical properties of the resulting component that needs to be accurately controlled for desired quality. SLM has been used to manufacture the components from CoCr alloys due to its capability to control the different process parameters accurately. The present review deals with the use of SLM-built CoCr alloys in biomedical applications.