Effects of Mo Addition on the Mechanical Properties and Microstructures of Ti-Mn Alloys Fabricated by Metal Injection Molding for Biomedical Applications

Abstract

Ti-Mn alloys fabricated by metal injection molding (MIM) show promising performance for biomedical applications, but their low ductility (caused by high O content and the presence of pores and carbides) requires improvement. Previously, the addition of Mo to cold crucible levitation melted (CCLM) Ti-Mn alloys ef ciently improved the ductility of those alloys by promoting mechanical twinning. In the present study, Mo was added to Ti-Mn alloys fabricated by MIM. Unlike fabrication by CCLM, fabrication by MIM can produce alloys with a smaller grain size, and also introduce microstructures such as pores and Ti carbides. Thus, in order to investigate how Mo addition interacts with these typical MIM features, four alloys for biomedical applications were fabricated by MIM: Ti-5Mn-3Mo (TMM-53), Ti-5Mn-4Mo (TMM-54), Ti6Mn-3Mo (TMM-63), and Ti-6Mn-4Mo (TMM-64). Their microstructures, mechanical properties, and tensile deformation mechanisms were evaluated. Their hardness values range from 312-359 HV, and their Young s modulus values range from 84-88 GPa; both the Vickers hardness and Young s modulus show little variation among the alloys. Although the alloys show fracture features associated with a predominantly ductile fracture mode and Mo addition successfully promotes mechanical twinning in TMM-54, the elongation of these alloys is still critically low. Compared to the TMM alloys fabricated by CCLM, the TMM alloys fabricated by MIM show slightly lower hardness and Young s modulus, and comparable tensile strength, with their low elongation remaining inadequate for such applications. In particular, TMM-63 shows the best combination of mechanical properties among the present alloys, with an elongation of 4% and an ultimate tensile strength of 1145 MPa.

β-Ti-Based Alloys for Medical Applications

“…Поэтому возникла необходимость в создании титановых сплавов с низким модулем Юнга и дешевыми легирующими добавками. В соответствии с этими требованиями были созданы сплавы Ti-Mn [57], Ti-Mn-Fe [58], Ti-Mn-Mo [59] и Ti-Mn-Al [60]. К подобным недорогим материалам относятся и Ti-10Cr-Al [61], Ti-Cr-Al [62], Ti-Sn-Cr [63], Ti-Cr-Sn-Zr [64,65] и Ti-12Cr [66], которые содержат высокие концентрации дешевых элементов, таких как марганец, хром и олово.…”

Design and development of metallic biomaterials with biological and mechanical biocompatibility

“…Therefore, low‐cost β‐type Ti alloys with low Young's moduli are desired. Based on this demand, Ti‐Mn, Ti‐Mn‐Fe, Ti‐Mn‐Mo, and Ti‐Mn‐Al alloys were designed. Other similar types of alloys include Ti‐10Cr‐Al, Ti‐Cr‐Al, Ti‐Sn‐Cr, Ti‐Cr‐Sn‐Zr, and Ti‐12Cr .…”

Microstructure, phase composition and mechanical properties of new, low cost Ti-Mn-Nb alloys for biomedical applications

“…To the authors' best knowledge, there are limited studies addressing the properties of Ti-Mn based alloys [18,21]. Therefore, this research aims to study a series of new Ti-Mn-Nb alloys prepared by conventional powder metallurgy (PM) from blended elemental powders.…”

“…Also, some micro-cracks can be seen which may have originated from the pores in the alloy microstructure acting as stress concentrators during compression testing. , Ti-6Mn-3Mo (E = 87 GPa) [21] and Ti-35Nb-10Ta-3Fe (E = 98 GPa) [51]. Furthermore, although the strain to failure of the Ti-7Mn-xNb alloys is lower than that of CP-Ti, the values are higher than other Ti alloys such as Ti-10Nb-3Mo (ߝ = 29%) [38], Ti-6Al-4V ELI (ߝ = 24%) [18], Ti-13Nb-(0-6)Zr (ߝ = 20-26%) [52] and Ti-(2-25)Cu (ߝ = 15-28%) [53].…”