Isothermal Aging Behavior of Beta Titanium–Manganese Alloys

Abstract

Although titanium is considered to be a ubiquitous element as it has the 10th-highest Clarke number of all the elements, it is actually classified as a rare metal because the current refinement process for the metal is more environmentally damaging than the processes used to refine iron and aluminum. Furthermore, the principal alloying elements of titanium alloys are very expensive, owing to their low crustal abundances; this is especially true of the beta-stabilizing elements. Manganese is also considered to be a ubiquitous element as it has the 12th-highest Clarke number of all the elements. Therefore, manganese is promising as an alloying element for titanium, especially as a beta-stabilizing element. In order to develop beta titanium alloys as ubiquitous metallic materials, it is very important to investigate the properties of Ti-Mn alloys. In this study, the phase constitutions and isothermal aging behaviors of Ti-6.0 to 14.8 mass%Mn alloys were investigated by electrical resistivity and Vickers hardness measurements, X-ray diffraction (XRD), and optical microscopy. In 6.0 mass%Mn alloys quenched from 1173 K, both hexagonal close-packed martensite and the beta phase were identified by XRD, whereas only the beta phase was detected in 8.7 and 14.8 mass%Mn alloys. The resistivity at liquid nitrogen temperature was greater than that at room temperature between 6.0 and 14.8 mass%Mn. The Vickers hardness decreased with an increase in the Mn content up to 11.3 mass%Mn and then increased slightly. On aging at 673 K, the isothermal omega phase was precipitated in 6.0 to 11.3 mass%Mn alloys, while it was precipitated by aging at 773 K in 6.0 and 8.7 mass%Mn alloys. The Vickers hardness increased drastically on isothermal omega precipitation, whereas it increased slightly in the case of direct alpha precipitation with no isothermal omega precipitation.

Microstructures, mechanical properties and cytotoxicity of low cost beta Ti–Mn alloys for biomedical applications

“…Recent studies concerning Ti-Mn alloys include the investigation of Ti-8Mn in the production of Ti nanotubes [27], the isothermal aging behavior of Ti-Mn alloys [28], and the production of Ti-Mn alloys by powder metallurgy (PM) processes for use in biomedical applications [29,30]. A previous work analyzed the effect of sintering temperatures over the microstructures and mechanical properties of a pair of Ti-Mn alloys fabricated by metal injection molding (MIM), in the as-sintered condition [30].…”

Phase Constitution and Aging Behavior of Ti‐10 Mass% Mn‐Oxygen Alloys

“…In addition, aluminum is added to suppress isothermal omega phase precipitation. The effect of heat treatment on the properties of three Ti-Mn alloy systems, Ti-Mn [1], Ti-Mn-Al [2], and Ti-Mn-Fe [3], such as electrical resistivity, Vickers hardness, phase constitution from X-ray diffraction (XRD) measurements, and optical microscope observations have already been reported. Aluminum is a very important alpha stabilizing element among all alpha stabilizers for titanium, such as tin and oxygen.…”

Strengthening of β Ti–6Cr–3Sn alloy through β grain refinement, α phase precipitation and resulting effects on shape memory properties

“…Mechanical and shape memory properties of b titanium alloys are sensitive to ageing treatment due to transformation of b phase to isothermal o and/or a phase precipitates [22][23][24]. Mechanical and shape memory properties of our recently developed Ti-6Cr-3Sn alloy were slightly improved by ageing at 373 K due to fine scale isothermal o phase precipitation.…”