新型γ-TiAl合金的γ/α_2层片形成机理  

Formation Mechanism of γ/α_2 Full Lamellar in the New γ-TiAl Alloy

作　　者：罗媛媛[1,2] 奚正平[1] 毛小南[2] 杨义[2] 曾卫东[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072 [2]西北有色金属研究院,陕西西安710016

出　　处：《稀有金属材料与工程》2014年第4期896-900,共5页Rare Metal Materials and Engineering

基　　金：国家自然科学基金项目(51001088)

摘　　要：讨论了经过不同冷却速率、加热温度和保温时间对新型TiAl合金的γ/α2层片组织的影响。结果表明:热处理时间增加,层片晶团的晶粒有长大趋势,片层组织中出现层错,位错等缺陷;在不同冷却方式中,油冷组织中出现了块状γ,炉冷组织具有密集的层片。热处理温度在Tα相变点以上20℃内,片层晶团的晶粒最小,这是由合金中的弱β稳定元素Ta造成的。Microstructural characteristics of TiAl-3Ta-x（Cr, W） alloy have been investigated in various annealing conditions, including cooling rates, heating temperatures and holding time by optics microscope （OM）, X-ray diffraction （XRD） and transmission electron microscopy （TEM）. The results show that the α2＋γ grains grow with longer heat treatment time while the fault and the dislocation are found in the full lamellar microstructure. The massive ）, precipitate in the microstructure by oil quenching and the full lamellar microstructure occurs by furnace cooling. Besides, the grain size of full lamellar is the smallest in the microstructure at the heat treatment temperature from Ta to Ta＋20 ℃, which is caused by weak fl stable element Ta.

关 键 词：TiAl高温合金 相变 层片组织 

分 类 号：TG146.23[一般工业技术—材料科学与工程]