Microstructural characterisation of near- α titanium alloy Ti-6Al-4Sn-4Zr-0.70Nb-0.50Mo-0.40Si

摘要: Microstructural stability in the near-α titanium alloy (alloy 834) containing Ti-6Al-4Sn-4Zr-0.70Nb-0.50Mo-0.40Si (in weight percent), β and(α + β) solution-treated and quenched conditions, has been investigated. The transus for this is approximately 1333 K. Solution treatment phase field at 1353 K followed by quenching water room temperature resulted formation of α′ martensite platelets with high dislocation density stacking faults. Thin films are found to be sandwiched between interface phases, which, turn, interplatelet boundaries lath martensite. a subject much controversy literature. 1303 the(α near-equiaxed primary α transformed β. Both specimens were aged range 873 973 While aging —treated specimen K,(α β)-treated specimen, even lower 24 hours, caused precipitation suicides predominantly laths. Electron diffraction analysis confirmed them hexagonal suicide S2 witha = 0.702 nm andc 0.368 nm. above difference could attributed partitioning higher amount β- stabilizing elements as well silicide-forming condition. However, ordering theα′ was observed under all conditions studied. ordered domains due longer times, which cause local increases level theα-stabilizing elements.