FAST-Roll: Turning surplus titanium powder into high-performance plate
Research by Samuel Lister and Will Pulfrey demonstrates how powder consolidation and hot rolling can be combined to produce Ti64 plate from surplus additive manufacturing powder. Using FAST, powder was consolidated into a billet, from which a rectangular preform was extracted and hot rolled to 5mm.
Production of Sustainable, Low-Anisotropy Titanium Alloy Plates Using Combined Field-Assisted Sintering and Hot Rolling
Compared with conventionally manufactured, unidirectionally rolled Ti–6Al–4V, the FAST-Roll material developed weaker crystallographic texture and reduced crystallographic anisotropy, while avoiding pronounced macrozones. Tensile testing and comparisons with published fatigue data also demonstrated promising mechanical performance, highlighting the potential for a shorter manufacturing route that retains the value of surplus titanium powder.
The Problem & Current Landscape: Titanium alloy (Ti–6Al–4V) plate and sheet products are critical across aerospace, defense, and biomedical sectors due to their strength and corrosion resistance. However, traditional manufacturing relies on the Kroll extraction process and up to 40 complex thermomechanical steps, driving up costs significantly and limiting adoption in high-volume industries like automotive or civil infrastructure. Secondary titanium feedstock, such as oversized additive manufacturing powders and machining swarf, is often downgraded or wasted rather than recycled into high-value products.
Proposed Solution: The paper introduces a hybrid solid-state route termed "FAST-Roll." This technique first consolidates low-cost, surplus titanium powder into dense preforms using Field-Assisted Sintering Technology (FAST, also known as Spark Plasma Sintering), followed by standard hot rolling. The approach bypasses expensive melting steps, retains material value, and enhances supply chain resilience.
Powder Consolidation (FAST): Out-of-specification surplus Ti–6Al–4V powder (particle size 45–150 µm) was loaded into graphite tooling and consolidated into a large cylindrical billet (250 mm diameter) using a FAST furnace. The process was performed at 950 °C and 35 MPa pressure with a 30-minute dwell time.
Preform Extraction & Hot Rolling: A rectangular preform (200 × 150 mm) was cut from the consolidated billet, preheated to 950 °C, and hot-rolled using a reversing mill to an 80% thickness reduction (down to 5 mm). Progressive reheats were applied between passes to maintain processing temperature.
Post-Processing & Evaluation: The rolled plates underwent a mill annealing heat treatment (750 °C for 1 hour). Microstructural evolution, crystallographic texture, tensile performance, and high-cycle fatigue properties were thoroughly characterised and compared against conventional unidirectionally rolled Ti–6Al–4V plates.
Superior Material Homogeneity: The fine-grained, near-isotropic initial microstructure of the FAST billet prevents the formation of macrozones and strong directional textures typically found in conventional melt-wrought titanium plates. This results in significantly lower mechanical anisotropy, making the material easier to form during downstream sheet-metal fabrication.
Industrial & Economic Viability: FAST-Roll demonstrates that surplus or secondary titanium feedstocks can be directly converted into flat products using existing industrial hot-rolling infrastructure without compromising mechanical performance.
Broad Application & Sustainability: By providing a low-cost, short-step processing route, this method opens new commercial opportunities for titanium in automotive electric vehicles, land defense, and structural engineering while lowering environmental footprint through scrap/powder recycling.
Associated paper: FAST-Roll: Texture Evolution and Mechanical Property Assessment of Low-Cost Ti–6Al–4V Plate from Surplus Powder