M-7 Influence of Laser Melting on Surface Layer Properties of Titanium Alloy Ti6Al4V

Abstract

In time of rapid technology and medicine progress, implants are becoming more widely used in the human body, ranging from dental implants, stabilizing plates, screws, orthopaedic prostheses. For example, there are many types of hip prostheses used for hip replacement as well as various types of materials used for these orthopaedic prostheses. Properties of titanium alloys used in hip prostheses combined with good strength properties, corrosion resistance and low modulus of elasticity, are the most compatible of all prosthetic materials such as cobalt alloys, corrosion resistance steel. However, their major drawback is the low wear resistance. In order to tackle this drawback the solution may be a hardening of the surface while maintaining the core characteristics. The laser melting process is the method that is utilized for precise and selective treatment of the surface layer. By concentrating a large portion of energy in a small area, laser technology allows to obtain better structures [1-3] than produced in traditional process [4]. This article presents the investigations results of titanium alloy Ti6Al4V surface layer after laser melting process. The process of laser melting was performed using Nd-YAG laser. Individual samples were laser melted using different scanning speeds and different shifts in the laser beam. The evaluation of structure of the alloy as well as hardness and chemical composition was performed. It was shown that laser melting changes the structure and properties of titanium alloy Ti6Al4V, process parameters as scanning speed affects the thickness of zones in upper layer of the material. Due to the laser melting process more wear resistive surface can be obtained that increases the wear and corrosion resistance of orthopeadic prosthesis.