Evaluation and Analysis of Distortion of Complex Shaped Ti-6Al-4V Compacts by Metal Injection Molding Process

Abstract

Titanium and its alloys have been widely used for medical and aerospace applications because of their excellent attributes of high specific strength, corrosion resistance, and biocompatibility. However, it is not easy to produce the complex shaped parts due to their poor castability and machinability. Metal injection molding (MIM) is one of suitable processing technique to produce the complex shaped parts in order to reduce the manufacturing cost. In this study, complex shaped Ti-6Al-4V compacts was prepared by MIM process for airplane application. The effects of high molecular binder content and different compact’s set-up during thermal debinding on the distortion of complex shaped compacts were measured and evaluated. The binder with 10 % APP (Atactic polypropylene) was found to have better shape retention for the parts. Furthermore the results indicate that high distortion occurs at early stage of thermal debinding process. The use of supports during thermal debinding can significantly reduce the distortion of the final parts.

Precision Mold of Prototype Titanium Orthopedic Implant using Metal Injection Molding Approach

“…The strength of the material is 450 MPa (65 ksi), with variations depending on composition and temperature. The material used for the implant component is Titanium base alloy Ti CP grade 2 [15].…”

“…Diverse in metal powder sizes will cause an impact on the homogeneous and solidity of the feedstock when injected. Binder as an additive to metal powders consists of polymer, wax and additive agent [15,16].…”

Metal injection moulding of titanium and titanium alloys: Challenges and recent development

“…While Ti64 is extensively used in the aerospace industry, the high quality standards required for application of any component in aerospace, means the MIM process faces significant hurdles before it can be accepted by this industry. Nonetheless, research has demonstrated that it is possible for the MIM process to manufacture Ti64 components with superior mechanical properties close to the ASTM standard range [5,43,51,100,101] especially by small addition of other elements such as B [43,45], C [71], Gd [58] and TiC [81]. However, most research work on MIM of Ti64 alloy has been specifically designed for biomedical applications [43,83,102] rather than other applications such as aerospace.…”

“…ability to manufacture complex parts and rapid production) to manufacture small-to-medium sized intricate components and is particularly suited to mass production [4]. The process offers significant design freedom in shape complexity but most MIM parts are restricted to smaller than about 100 mm in size for high dimensional accuracy and consistency [3,5].…”

Control the Distortion of the Large and Complex Shaped Parts by the Metal Injection Molding Process

“…However, in the case of the large sized parts, it becomes difficult to control the distortion and cracking because of the remained binder in the thick part and the large shrinkage during debinding and sintering process 2,3) . These defects were affected by gravity, friction and inhomogeneity of green density [4][5][6] .…”