机械球磨对Ti/Al混合粉末组织和热稳定性影响的研究

Investigation on the influence of mechanical milling on microstructure and thermostability of Ti /Al mixed powders

为了探索一种制备高综合性能TiAl基金属间化合物的新方法,研究了机械球磨对Ti、Al粉末微观组织及其热稳定性的影响.结果表明:在机械球磨的作用下Al粉末晶粒以高于Ti的速率细化,最终形成局部含少量Ti纳米晶的非晶,但在整个过程中未发现Ti、Al元素相互扩散形成Ti-Al金属间化合物中间相;不同球磨时间作用下的Ti/Al粉末中贮有不同的能量,且随时间的延长而增加,以非晶化粉末最为显著,内能的增加是由于机械合金化过程引入了大量的微观缺陷所致.对不同球磨时间的粉末进行热处理显示,球磨时间的增加可大幅度降低形成Ti-Al金属间化合物的温度,球磨75h的复合粉末甚至在350℃,保温1h即可转变成金属间化合物.Ti/Al摘要:为了探索一种制备高综合性能TiAl基金属间化合物的新方法,研究了机械球磨对Ti、Al粉末微观组织及其热稳定性的影响.结果表明:在机械球磨的作用下Al粉末晶粒以高于Ti的速率细化,最终形成局部含少量Ti纳米晶的非晶,但在整个过程中未发现Ti、Al元素相互扩散形成Ti-Al金属间化合物中间相;不同球磨时间作用下的Ti/Al粉末中贮有不同的能量,且随时间的延长而增加,以非晶化粉末最为显著,内能的增加是由于机械合金化过程引入了大量的微观缺陷所致.对不同球磨时间的粉末进行热处理显示,球磨时间的增加可大幅度?

In order to explore a new process of fabricating TiAl intermetallic compounds with favorable combination of properties,the effect of mechanical milling on microstructure and thermostability of Ti-36Alwt.%Al was investigated.The experimental results show that Al grain size decreases more rapidly than Ti during milling,and that the powders transform into amorphous base inlaid by a little amount of nanometer-grain ed Ti.However,no TiAl compound is observed to appear during the whole process.The composite powders under different mechanical milling times store corresponding energy,and the energy increases with milling time ,and thus amorphous powders obtain the maximum energy.It is mechanical milling that causes plenty of defects such as lattice distortion so as to raise the internal energy.Heat treatment results of powders milled for different time s present that the increase of mechanical milling time leads to a temperature promptly declined at which the75h milled mixed powders can transform into intermetallic compound evening after1hannealing at350℃.