(中南工业大学粉末冶金国家重点实验室， 长沙410083
中南工业大学材料科学与工程系， 长沙410083)
摘 要: 用Gleeble1500热模拟机研究了双温循环热处理对铸态TiAl基合金显微组织的影响。 结果表明， 用双温循环热处理可显著细化铸态合金的晶粒尺寸， 最小平均晶粒尺寸可达10μm左右， 且晶粒大小均匀； 新晶粒主要在晶界形核， 并逐步向晶内扩展。 经循环热处理后的样品， 比铸态硬度提高300～900 MPa。
关键字: TiAl基合金 循环热处理 显微组织 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
