A low-cost hierarchical nanostructured beta-titanium alloy with high strength

Abstract

Lightweighting of automobiles by use of novel low-cost, high strength-to-weight ratio structural materials can reduce the consumption of fossil fuels and in turn CO2 emission. Working towards this goal we achieved high strength in a low cost β-titanium alloy, Ti–1Al–8V–5Fe (Ti185), by hierarchical nanostructure consisting of homogenous distribution of micron-scale and nanoscale α-phase precipitates within the β-phase matrix. The sequence of phase transformation leading to this hierarchical nanostructure is explored using electron microscopy and atom probe tomography. Our results suggest that the high number density of nanoscale α-phase precipitates in the β-phase matrix is due to ω assisted nucleation of α resulting in high tensile strength, greater than any current commercial titanium alloy. Thus hierarchical nanostructured Ti185 serves as an excellent candidate for replacing costlier titanium alloys and other structural alloys for cost-effective lightweighting applications.

A Review of Metastable Beta Titanium Alloys

“…A study on the metastable Ti-1Al-8V-5Fe (wt. %) alloy, which has a MoE value of 18.9, by Devaraj et al, evaluated varying sub-transus solution treatment temperatures on tensile and fatigue properties [103]. These authors reported that solution treatment at a temperature closest to the quantity T β gave the highest yield strength and tensile strength values, which was attributed to greater volume fraction of nanoscale secondary α-phase precipitates uniformly distributed in the bcc β-phase matrix.…”

Processing of Beta Titanium Alloys for Aerospace and Biomedical Applications

“…Choice of solution treatment temperature is important. For example, for Ti-1Al-8V-5Fe (Ti185), solution treatment near beta transus temperature leads to a highest tensile and yield strength [19].…”

Atom Probe Tomography: Development and Application to the Geosciences

“…(a) Coarsening of NiAl and Cu‐rich particles within a steel weld (figure 11 of Jiao et al . ); (b) element partitioning between alpha and beta phases following heat treatment of a high‐strength titanium alloy (Devaraj et al ); (c) partitioning of carbon (red dots) between ferrite and martensite phases in a decarburised alloy (figure 3 of Van Landeghem et al . ); (d) V‐pit defect distorting InGaN/GaN quantum well layers (grey dots are Ga atoms and In isoconcentration surfaces are in blue) showing Mg dopant (red spheres) distribution (figure courtesy of Rob Ulfig, Cameca); (e) fine‐scale clustering in an Al‐Cu‐Mg alloy.…”