The Technological Design of Geometrically Complex Ti-6Al-4V Parts by Metal Injection Molding

Shulong Ye,Wei Mo,Chi Tat Kwok,Yonghu Lv,Peng Yu,Zhanhua Wang

doi:10.3390/app9071339

Shulong Ye, Wei Mo + Show 4 more

Open Access

https://doi.org/10.3390/app9071339

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Abstract

In this study, the metal injection molding (MIM) process is applied to produce Ti-6Al-4V parts using blended and prealloyed powders, respectively. The feedstocks are prepared from a polyformaldehyde-based binder system with a powder loading of 60 vol%, exhibiting a low viscosity. The decomposition behavior of the binders is investigated and the thermal debinding procedure is designed accordingly. The debound parts are subsequently sintered at 1200 and 1300 °C. The results show the mechanical properties of the sintered samples prepared from blended powder are comparable to those prepared from prealloyed powder, with yield strength of 810 MPa, ultimate tensile strength (UTS) of 927 MPa, and elongation of 4.6%. The density of the as-sintered samples can reach 4.26 g/cm3 while oxygen content is ~0.3%. Based on the results, watch cases with complex shapes are successfully produced from Ti-6Al-4V blended powder. The case gives a good example of applying metal injection molding to mass production of precise Ti-6Al-4V parts with complex shapes in a cost-effective way.

Highlights

Ti-6Al-4V is one of the most important and widely used titanium alloys, exhibiting specific mechanical properties, good biocompatibility, and outstanding corrosion resistance
Ti-6Al-4V samples were successfully fabricated by metal injection molding from both blended and prealloyed powders
Ti-6Al-4V samples were successfully fabricated by metal injection molding from both blended feedstock prepared by the blended powder is lower than that prepared by the prealloyed powder, and prealloyed powders

Summary

Introduction

Ti-6Al-4V is one of the most important and widely used titanium alloys, exhibiting specific mechanical properties, good biocompatibility, and outstanding corrosion resistance. It has been applied in the aerospace, biomechanical, and electronic industries [1]. The poor machinability and high manufacturing cost for complex shaped components limit its further applications. To solve these problems, the metal injection molding (MIM) process of Ti-6Al-4V is becoming more and more attractive in both research and industry [5,6,7]. A Ti-6Al-4V part manufactured from blended powder is demonstrated, showing the possibility of industrial application of the cost-reducing process

Materials and Methods

Discussion

SEM fracture surfaces

Circular

Optical

Conclusions