(中南大學 粉末冶金國家重點實驗室，長沙 410083)
摘 要: 研究了兩步熱處理對鍛造Ti-47Al-2Cr(摩爾分數，%)組織演變和室溫拉伸性能的影響。經1290℃，4h→1240℃(FC)，4h，FC+900℃，24h熱處理后，鍛造TiAl基合金中形成了均勻細小的雙態(tài)組織，其室溫伸長率, 室溫抗拉強度和室溫屈服強度分別為3.5% , 677MPa和597MPa。在熱處理過程中，鍛造TiAl基合金發(fā)生了復雜的相變，其相變 過程為：變形組織→γf+αf→γf+(αf+γs+αs)→γf+Lf+γs+Ls。當第二步熱處理溫度偏低時，αs轉變?yōu)榇嘈?I>α2相顆粒，降低了合金的室溫拉伸性能。
關鍵字: TiAl基合金；熱處理；室溫拉伸
TiAl-based alloy made by two-step heat
treatment
LIU Wen-sheng，TANG Zhi-hong，LU Shi-qiang
（State Key Laboratory for Powder Metallurgy，
Central South University，Changsha 410083，China）
Abstract:The effect of two-step heat treatment on the microstructure evolution and room tensile properties of forged Ti-47Al-2Cr (mole fraction, %) was investigated. After the heat treatment of 1290℃，4h→1240℃(FC)，4h，FC+900℃， 24h，the uniform fine duplex microstructures are formed in forged TiAl-based alloy and its room temperature tensile ductility，tensile strength and yield strength reach 3.5%， 677MPa and 597MPa respectively. The formation of uniform fine duplex microstructures results from the complex phase transformation of forged microstructures→γf+αf→γf+(αf+γs+αs)→γf+Lf+γs+Ls. When the temperature of the second step heat treatment is lower，the transformation of αs into brittle α2 phase particles leads to the decrease of room temperature tensile properties.
Key words: TiAl-based alloy; heat treatment; room temperature tensile
