摘要
采用机械合金化结合粉末冶金技术制备Ti-44．7Al、Ti-44．7Al-xw、Ti-44．7Al-xLa-yCe合金材料，采用透射电镜和金相显微镜研究不同W、La、Ce添加量对机械合金化TiAl基合金的显微组织的影响，并对合金的力学性能进行测试。研究表明，在不添加任何元素时TiAl合金颗粒的平均尺寸为30-60μm，但添加微量稀土元素La、Ce对TiAl基合金的细化作用非常明显，其平均尺寸为20μm；通过机械合金化在TiAl基合金系统中添加微量W元素会形成新的固溶体相，这种新成分相大大提高TiAl基合金的抗弯强度σb，当W添加量为1．0％时，σb达到峰值，随后随着W原子数分数的增加，抗弯强度降低；TiAl合金的抗弯强度σb开始随着稀土元素La的增加而增加，在0．5％原子数分数处达到峰值，然后强度随稀土原子数分数的继续增加而下降；而合金的强度却随添加Ce的原子数分数的增加而直线下降，同时添加W的TiAl合金的强度高于加稀土La、Ce的TiAl合金的强度。
Ti-44. 7Al, Ti-44. 7Al-xW and Ti-44. 7Al-xLa-yCe alloys were prepared by mechanical alloying with subsequent traditional powder metallurgy technique. The effect of the different W, La and Ce contents on microstructure and high temperature oxidation property of TiAl alloy was investigated by using transmission electron microscopy and the metallographic microscope, and the mechanical property of the alloy was measured. The results show that the grain of the TiAl alloy without adding any element has an average size from 30μm to 60 μm, but the minim adding of the rare earth elementsLa and Ce to the TiAl based alloy system has obvious effect on thinning the alloy and the grain ot the TiAl alloy has an average size of 20μm. In the system of the Ti-Al alloy, new solid solution phases were formed because of the tungsten addition. Meantime, the bending strength of the TiAl matrix alloy is reinforced by the new phases. The value of the bending strength peaks when the W addition amount reaches 1.0%, and later decreases with the increase in the W content. The bending strength of Ti-Al alloy is reinforced by the La addition, and the bending strength reaches the peak when the La addition is up to 0. 5 %, and later decreases with the increase in the La content. But the bending strength of the alloy is decreased rapidly with the increase in the Ce content. Meanwhile the bending strengthof the alloy with W is much higher than that with the addition of La and Ce.
出处
《合肥工业大学学报（自然科学版）》
CAS
CSCD
北大核心
2009年第11期1707-1710,共4页
Journal of Hefei University of Technology：Natural Science
基金
安徽省自然科学基金资助项目(070414180)
合肥工业大学创新群体基金资助项目(103-037016)
关键词
机械合金化
稀土元素
TIAL基合金
显微结构
抗弯强度
mechanical alloying
rare earth element
TiAl matrix alloy
microstructure
bending strength
