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

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.

Interactions of polymeric components in a POM-based binder system for titanium metal injection moulding feedstocks

“…At present, the interaction of the binder and powder is mainly assessed by rheological and thermogravimetry measurements [3,[15][16][17]. Very little is known about the specific interactions among binder components and how such interaction affects the MIM of reactive powders, such as Ti-MIM.…”

Improving the Melt Flow Length of Acrylonitrile Butadiene Styrene in Thin-Wall Injection Molding by External Induction Heating with the Assistance of a Rotation Device

“…Related to the melt flow in the cavity, the appearance of a frozen layer is the main reason for a reduction in the filling ability. To address this challenge, a number of methods have been tested, with the aim of reducing the filling pressure [ 7 ] and the viscosity of the melt material [ 8 , 9 , 10 ] or increasing the filling speed. When the aim was to increase the filling pressure, a high injection pressure was selected, and the experiment showed that the melt flow length was improved.…”