Exploitation of field assisted sintering technology (FAST) for titanium alloys

Abstract

Field assisted sintering technology (FAST), also known as spark plasma sintering (SPS), is increasingly utilised to process powders/particulates of engineering alloys and metal-based composite materials. FAST is currently extensively used at laboratory scale by research institutes and universities as a rapid and cost‑effective process to consolidate powders. This includes investigating new alloy compositions and material combinations, improving established materials’ properties, and consolidating materials considered challenging/impossible through conventional sintering techniques. FAST is gaining traction for industrial applications with possible benefits as an alternative to hot isostatic pressing or conventional melt-wrought processing. FAST preform complexity is improving and near-net-shape components are becoming a possibility. Demonstrator components for the aerospace and automotive sectors, including aeroengine blades, brake callipers and rocker arms, have been produced from titanium alloy powders. FAST has also been demonstrated as an effective intermediate step for consolidating a range of feedstocks, including recycled materials, into shaped billets that can be further processed to refine shape and/or properties. Hybrid processes such as FAST‑forge and FAST‑DB have been developed that can produce affordable titanium components with forged properties. This paper presents the current status, emerging developments, and challenges of FAST for titanium-based powders and particulates.

Effect of processing route on ballistic performance of Ti-6Al-4V armour plate

“…The rolled plate is ASTM 256 Ti-6Al-4V Grade 5 in the mill-annealed condition. Two FAST plates of 250 mm diameter were produced using surplus Ti-6Al-4V powder using The University of Sheffield's FCT HP D250 machine, where a large amount of prior research has been carried out into the consolidation of titanium particulates via FAST [13,17,29,30], using a sintering cycle of 30 min dwell time at 1100°C or 950°C with a uniaxial pressure of 35 MPa, with no further heat treatment. The HIPed plate was manufactured by BAE Systems to a proprietary BAE Systems HIP cycle.…”

“…Alternatively, Hot Isostatic Pressing (HIP) and Field Assisted Sintering Technology (FAST) are direct solidstate consolidation techniques that enable near-net shapes to be produced in one single step, using vacuum or protective atmospheres, with the proven capability to use lower-cost titanium powder and particulate feedstock in the FAST process [10][11][12][13]. HIP is the most common method used for consolidating titanium alloy powders, which are hermetically sealed in a mild or stainless steel can [14].…”

Investigation of the Properties of Powder Materials Using Computer Modeling

“…1). The mass of this fraction is attributed to the sum of the masses of all fractions and multiplied by 100, which is the percentage of this fraction in the sample (%) [19,20]:…”

Improvement of Processes for Obtaining Titanium Alloys for Manufacturing Parts with Design Elements

“…Research teams [8] investigated the interaction zone between titanium and aluminium in a composite obtained by immersion and exposure of titanium rods in an aluminium melt. It was [9] found that the heat treatment time and cooling conditions affect the thickness and structure of the transition layer formed as a result of the interaction. The results of [10] show the peculiarity of porosity and coordination number calculations.…”