| dc.description.abstract | In recent years, the technology of laminated manufacturing has been widely applied to the production of orthopedic implants, which can replace, support, fix or repair damaged tissues. Titanium alloy is one of the materials of choice for orthopedic implants. The main characteristics of titanium alloy, such as biocompatibility and corrosion resistance, meet the needs of orthopedic implants; however, titanium alloy is susceptible to reactive reactions due to high temperatures and gases during the processing of titanium alloys, making titanium alloys one of the most difficult metals to process in conventional manufacturing. The laminated manufacturing process does not have the constraints of conventional manufacturing, and selective laser melting is most commonly used in the laminated manufacturing of titanium alloys. The main reason is that the high temperatures generated during the process can completely melt the titanium alloy, which in turn increases the mechanical properties of the finished product. However, the repeated high-temperature melting in this process makes the finished products go through the process of heating and cooling continuously, and the rate of cooling temperature dropping is too large, which generates residual stress inside and leads to inaccuracy or deformation of the manufacturing. In order to reduce the residual stress, heat treatment is the most common method. Atmospheric or vacuum heat treatment furnaces are used to prevent the titanium alloy from reacting with oxygen. However, heat treatment furnaces and consumables are quite expensive, resulting in increased costs for heat treatment after the laminate has been manufactured.
The purpose of this study is to develop a method to reduce the warpage caused by internal stress and to reduce the cost of heat treatment by using an atmosphere-free or vacuum high-temperature furnace for the heat treatment of laminated fabrication. In this study, silicon carbide is used to prevent oxygen penetration and sealed in a container to reduce the air circulation and avoid the reaction between oxygen and titanium to form titanium oxide at high temperature, and to study the effect of different heat treatment parameters on the mechanical properties of the specimens. The experimental results show that the warpage of 20mm at both ends of the clamping side of the fabricated heat treatment for metal lamination is reduced from 400μm to 76μm, which is more than five times of the warpage, and the yielding stress is larger than that of the atmosphere heat treatment. Finally, the design and process of heat treatment in the preparation type are proposed to be improved in order to achieve the goal of subsequent improvement. | en_US |