机械合金化过程中Fe70B30粉末晶粒尺寸和微观应变的研究

用Ｘ射线和电镜研究了Ｆｅ＿（７０）Ｂ＿（３０）粉末经不同时间高能球磨后晶粒尺寸和微观应力的变化。在机械合金化过程中，粉末的Ｘ射线衍射谱的宽度随球磨时间的增加逐渐加宽，这是晶粒细化和内部微观应力共同作用的结果。Ｘ射线衍射结果表明：随着机械合金化的进行，粉末的晶粒尺寸逐渐减小，球磨初期晶粒尺寸下降较快，经１５ｈ球磨，晶粒尺寸为２５ｎｍ，机械合金化进行到一定时间后晶粒尺寸下降缓慢，８０ｈ球磨后晶粒尺寸可达５ｎｍ。在机械合金化过程中球磨所造成的微观应变不大，球磨初期粉末的内应力随球磨时间增加而增加，当粉末粒子尺寸很小时，随球磨的进行粉末中的微观应变显著下降。

Study of Crystal Size and Microstrain by Mechanical Alloying on Fe_(70)B_(30) Powder

Crystal size and microstrain caused by mechanical alloying on Fe_(70)B_(30) powder were studiedby X-ray diffractometry and transrnission electronmicroscopy. During the mechanical alloying, thewidth of the x-ray diffraction lines increases withball milling time , it is caused both by the reductionof crystal size and the increase of microstrain. Byanalysing the x-ray diffraction lines,we got theresults as following: the crystal size of Fe_(70)B_(30)powder decreases when increaseing milling time inthe case of mechanical alloying of Fe and B powdermixtures.The microstrain increase with milling timeat the early stage of milling and begain to decreaseafter 80 h milling. The grain size of Fe_(70)B_(30) powderafter 80h milling is about 5 nm which is determinedby the Scherrer formula.