激光选区熔化TiAl合金成形和组织演变规律及机制OA

TiAl alloys exhibit poor room-temperature ductility,which poses a challenge for traditional casting and forging processes to fulfill the manufacturing demands for complex structural components.Selective laser melting(SLM)technology,renowned for its short manufacturing cycle,high material utilization,and exceptional forming accuracy,is deemed well-suited for fabricating complex parts in the aerospace industry.In this research,Ti48Al2Cr2Nb alloy powder is mixed with 4%(mass fraction)FeMo60 alloy powder to formulate an alloy with a nominal composition of Ti47Al3.5Cr1Nb1Mo1Fe.By employing a chessboard overlap scanning strategy(which mitigates thermal stress during processing)and optimizing printing parameters,SLM fabrication of the TiAl alloy with a remarkably low defect rate(only 0.49%)is successfully accomplished.Moreover,the samples are characterized using X-ray diffraction and scanning electron microscopy to explore the underlying reasons for microstructure formation.Additionally,a substantial portion of the α2 phase in the as-printed alloy is converted into the γ phase through heat treatment.Simultaneously,the unmelted FeMo60 powder from the printing process is dissolved,achieving solid solution strengthening.This phenomenon leads to a significant 30%enhancement in the compressive strength.This study offers a crucial reference for the preparation of high-performance TiAl alloys with complex geometries.