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

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.

[1]  B. Friedrich,et al.  Characteristics of Ti6Al4V Powders Recycled from Turnings via the HDH Technique , 2018 .

[2]  C. Leyens,et al.  Titanium and Titanium Alloys , 1954 .

[3]  T. Ebel,et al.  High cycle fatigue behaviour of Ti–6Al–4V fabricated by metal injection moulding technology , 2009 .

[4]  L. Yu,et al.  Dehydrogenation debinding process of MIM titanium alloys by TiH2 powder , 2006 .

[5]  V. Günay,et al.  Effect of sintering parameters on mechanical properties of injection moulded Ti–6Al–4V alloys , 2009 .

[6]  Yao Jiang,et al.  Fabrication of Ti–Al Micro/ Nanometer‐Sized Porous Alloys through the Kirkendall Effect , 2007 .

[7]  T. Ebel,et al.  Influence of processing parameters on mechanical properties of Ti–6Al–4V alloy fabricated by MIM , 2010 .

[8]  Qu Xuan-hui,et al.  Powder injection molding of Ti–6Al–4V alloy , 2006 .

[9]  P. Yu,et al.  Metal Injection Molding of Thin-Walled Titanium Glasses Arms: A Case Study , 2018 .

[10]  Brady G. Butler,et al.  Feasibility of Using Titanium Machine Turnings in Powder Metallurgy Processes , 2019, JOM.

[11]  T. Ebel,et al.  Influence of surface quality and porosity on fatigue behaviour of Ti–6Al–4V components processed by MIM , 2010 .

[12]  James K. Wessel,et al.  Handbook of advanced materials : enabling new designs , 2004 .

[13]  S. Atre,et al.  Rheological and thermal debinding properties of blended elemental Ti-6Al-4V powder injection molding feedstock , 2017 .

[14]  T. Ebel.  Metal injection molding (MIM) of titanium and titanium alloys , 2019, Handbook of Metal Injection Molding.

[15]  T. Ebel,et al.  Metal injection molding of titanium , 2015 .

[16]  P. Cao,et al.  Development and Design of Binder Systems for Titanium Metal Injection Molding: An Overview , 2013, Metallurgical and Materials Transactions A.

[17]  T. Ebel,et al.  Ti–6Al–4V–0.5B—A Modified Alloy for Implants Produced by Metal Injection Molding , 2011 .

[18]  Z. M. Wang,et al.  Titanium alloys and their machinability—a review , 1997 .

[19]  F. Frees.  Powder Injection Molding (Pim) Of Titanium Alloys - Ripe For Expansion , 2000 .

[20]  T. G. Kang,et al.  Experimental and Numerical Analysis of Injection Molding of Ti-6Al-4V Powders for High-Performance Titanium Parts , 2018 .

[21]  D. StJohn,et al.  Metal injection moulding of titanium and titanium alloys: Challenges and recent development , 2017 .

[22]  R. German.  Progress in Titanium Metal Powder Injection Molding , 2013, Materials.

[23]  C. Leyens,et al.  Titanium and titanium alloys : fundamentals and applications , 2005 .

[24]  P. Yu,et al.  Effects of cold compacting pressure on the expansion behavior of Ti-48Al during sintering , 2016 .

[25]  Z. Fang,et al.  Review of the Methods for Production of Spherical Ti and Ti Alloy Powder , 2017 .

[26]  R. German,et al.  Rheological and Thermal Debinding Behaviors in Titanium Powder Injection Molding , 2009 .

[27]  K. Weil,et al.  Microstructure and mechanical properties of titanium components fabricated by a new powder injection molding technique , 2005 .