(中南工業(yè)大學粉末冶金國家重點實驗室， 長沙410083
中南工業(yè)大學材料科學與工程系， 長沙410083)
摘 要: 用Gleeble1500熱模擬機研究了雙溫循環(huán)熱處理對鑄態(tài)TiAl基合金顯微組織的影響。 結(jié)果表明， 用雙溫循環(huán)熱處理可顯著細化鑄態(tài)合金的晶粒尺寸， 最小平均晶粒尺寸可達10μm左右， 且晶粒大小均勻； 新晶粒主要在晶界形核， 并逐步向晶內(nèi)擴展。 經(jīng)循環(huán)熱處理后的樣品， 比鑄態(tài)硬度提高300～900 MPa。
關(guān)鍵字: TiAl基合金 循環(huán)熱處理 顯微組織 晶界形核
CYCLIC HEAT TREATMENT ON
MICROSTRUCTURE OF TiAlBASED ALLOY
（The State Key Lab of Powder Metallurgy;
* Department of Materials Science and Engineering,
Central South University of Technology, Changsha 410083, P.R.China）
Abstract:The effect of double-temperature cyclic heat treatment on microstructure of a TiAlbased alloy(Ti-33Al-3Cr, mass fraction, %) was studied by means of Gleeble-1500 thermal stimulator. The results showed that the grain size of the as-cast
alloy samples can be obviously refined and the smallest average grain size reaches about 10μm, that the nucleations mainly occur at the grain boundaries and propagate into the grains, and that after cyclic heat treatment the HV5 hardness values are raised by 300～900 MPa.
Key words: TiAl-based alloy cyclic heat treatment microstructure grain boundary nucleation
