β凝固TiAl合金的包套锻造及组织优化  

Packed forging and microstructure optimization of β-solidified TiAl alloy

作　　者：邓志海[1] 李金山[1] 张铁邦[1] 钟宏[1] 常辉[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,西安710072

出　　处：《塑性工程学报》2012年第2期43-48,共6页Journal of Plasticity Engineering

基　　金：国家973计划资助项目(2011CB605502);凝固技术国家重点实验室资助项目(71-QP-2011)

摘　　要：采用Gleeble-1500D热力模拟机对Ti-43Al-5(Nb,Mo,B)(at.%)合金在不同温度和变形速率下的位移-载荷曲线进行实验研究,根据热模拟结果制定该合金的包套锻造工艺,成功实现了包套锻造,同时对合金的锻后组织及热处理组织进行分析。结果显示,该合金在热压缩过程中,载荷先快速升高,随后保持稳定,最后继续上升;在温度1150℃,以0.1/s的变形速率对合金铸锭进行一次包套锻造至工程变形量50%,获得了质量良好的合金锻坯。合金的锻后组织由大量弯曲、破碎的层片,细小的再结晶晶粒及少量残留β相和平直层片组成。经l180℃/5h热处理后,弯曲、破碎的层片通过静态再结晶和组织球化形成细小均匀的等轴晶粒,残留β相也基本消除,组织均匀性大幅提高。The displacement-load curves of Ti-43Al-5（Nb,Mo,B） alloy isothermally compressed at different strain rates and temperatures on Gleeble-1500D thermal-simulation machine were investigated.The results indicated that the load increased sharply first,and then kept constant,and finally increased again as the displacement increased continuously.A crack-free pancake was obtained when the ingot was packing forged at 1150℃ and with strain rate of 0.1/s.The microstructure of the pancake consisted of major kinked/broken lamellae and dynamic recrystallization grains,minor residual β phase and remnant lamellae.After annealed at 1180℃ for 5 hours,a homogeneous microstructure with fine and equiaxed grains was obtained.With elimination of the residual β phase,the uniformity of the microstructure was greatly improved as well.

关 键 词：热变形行为 等温压缩 包套锻造 Β相 组织均匀性 

分 类 号：TG146.2[一般工业技术—材料科学与工程]