High-strength Ti-Al-V-Zr cast alloys designed using α and β cluster formulas

Ti-Al-V-Zr quaternary titanium alloys were designed following α-{[Al-Ti12](AlTi2)}17−n+β-{[Al-Ti12Zr2](V3)}n, where n=1–7 (the number of β units), on the basis dual-cluster formula popular Ti-6Al-4V alloy. Such an alloying strategy aims at strengthening alloy via Zr and V co-alloying in β-Ti unit, based original [Al-Ti14](V2Ti) The microstructures as-cast by copper-mold suction-casting change from pure α (n=1) to α+α′ martensite (n=7). When n is 6, Ti-5.6Al-6.8V-8.1Zr reaches highest ultimate tensile strength 1,293 MPa yield 1,097 MPa, expense a low elongation 2%, mainly due presence large amount acicular α′ martensite. Its specific far exceeds that 35%.