CAJ | 학술논문

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30～60 μm,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20 μm;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.
채용궤계합금화결합분말야금기술제비Ti-44.7Al、Ti-44.7Al-xW、Ti-44.7Al-xLa-yCe합금재료,채용투사전경화금상현미경연구불동W、La、Ce첨가량대궤계합금화TiAl기합금적현미조직적영향,병대합금적역학성능진행측시.연구표명,재불첨가임하원소시TiAl합금과립적평균척촌위30～60 μm,단첨가미량희토원소La、Ce대TiAl기합금적세화작용비상명현,기평균척촌위20 μm;통과궤계합금화재TiAl기합금계통중첨가미량W원소회형성신적고용체상,저충신성분상대대제고TiAl기합금적항만강도σb,당W첨가량위1.0%시,σb체도봉치,수후수착W원자수분수적증가,항만강도강저;TiAl합금적항만강도σb개시수착희토원소La적증가이증가,재0.5%원자수분수처체도봉치,연후강도수희토원자수분수적계속증가이하강;이합금적강도각수첨가Ce적원자수분수적증가이직선하강,동시첨가W적TiAl합금적강도고우가희토La、Ce적TiAl합금적강도.
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 30 μm to 60 μm, but the minim adding of the rare earth elements La and Ce to the TiAl based alloy system has obvious effect on thinning the alloy and the grain of the TiAl alloy has an average size of 20 μm. 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 a-mount 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 strength of the alloy with W is much higher than that with the addition of La and Ce.