Microstructure design and mechanical properties in a near-α Ti–4Mo alloy

Atom probe tomography reveals options for microstructural design of steels and titanium alloys by segregation engineering

“…More specific, we present some recent results obtained on a plain binary Ti-4Mo (wt.-%) model alloy where we found different types of diffusion driven allotropic phase transformations and shear and / or diffusion dominated modes of martensitic transformations, enabling to realize a wide variety of efficient ways to design microstructures. The data presented here are taken from a recent publication [20]. Figure 5 shows an example where in a homogenized, water quenched and subsequently 950°C-550°C heat treated Ti-4Mo (wt.-%) solid solution model alloy pronounced elemental partitioning between a zone of hexagonal matrix α and an abutting zone of body centered cubic β is observed.…”

“…The water quench creates shear-dominated martensite and the subsequent tempering leads to the decomposition and Mo partitioning according to α′ → α + β. These thin ß-layers at the interfaces increase the toughness of the material [20].…”

“…Solid solution alloys based on Ti and minor additions of Mo, Nb, Fe or V reveal some similarities to steels: they show pronounced segregation effects and a variety of diffusional and athermal phase transformation phenomena between the hexagonal and the body centered cubic phases [20]. More specific, we present some recent results obtained on a plain binary Ti-4Mo (wt.-%) model alloy where we found different types of diffusion driven allotropic phase transformations and shear and / or diffusion dominated modes of martensitic transformations, enabling to realize a wide variety of efficient ways to design microstructures.…”

“…The microstructure was designed by imposing a solution heat treatment at 950°C in the β regime, followed by water quenching and a subsequent annealing treatment at 550°C. The APT elemental map and the corresponding 1-D concentration profile (bin width 0.5 nm) across the Mo enriched layer reveal the spatial distribution of the Mo atoms [20].…”

Study on Transformation Mechanism and Kinetics of α’ Martensite in TC4 Alloy Isothermal Aging Process

“…However, the microstructure and mechanical properties of the alloy often have significant differences due to the influence of alloy composition and external conditions (stress state, temperature, cooling rate, etc.) [3][4][5]. Therefore, it is necessary to systematically study and quantify the relationship between the law of microstructure evolution and the main process variables.…”