机械合金化工艺对Fe-Ni合金显微结构的影响

The Effect of Mechanical Alloying Technology on Microstrcture of Fe-Ni Alloy

对机械合金化制备的Fe-Ni粉体利用X射线衍射(XRD)进行分析,得到了不同Ni含量和不同球磨时间Fe-Ni纳米晶的XRD谱.实验表明,w(Ni)=10%和20%时,Ni溶入Fe晶格,分别在球磨20h和50h后形成单一的α(bcc)相;w(Ni)=50%时,其先后经历了γ(fcc) α(bcc)正逆转变,在球磨120h后最终形成单一γ(fcc)相.无论是α(bcc)相还是γ(fcc)相,它们的固溶度均比块体Fe-Ni合金显著提高.w(Ni)=35%时,则始终是两相共存.对试样的XRD谱采用3种不同的方法测定了Fe-Ni粉体的晶粒尺寸和显微畸变,发现经球磨20h后,不同Ni含量的粉体均呈纳米结构,并随球磨时间延长,Fe-Ni纳米晶的晶粒尺寸下降而显微畸变上升.

Fe-Ni nanocrystals with different Ni content were produced by mechanical alloying method through different milling time. X-ray diffraction (XRD) analysis indicated that in the samples with Ni content of 10% and 20%, Ni atoms entirely dissolved in the Fe lattice, and single α (bcc) phase forms after milling 20 h and 50 h respectively, while in the sample with 50% Ni, single γ (fcc) phase forms after milling 120 h, and the forward and backward transformations of γ (fcc) α (bcc) occur in turn. The solubilities of α (bcc) and γ (fcc) phase are obviously higher than those of their equilibrium conditions. The ( α (bcc)) and γ (fcc) phases in samples with 35% coexists during the whole milling time. Three XRD analysis methods were used to precisely measure grain size and microstrain, from which it was found that the grain sizes of Fe-Ni alloys with different Ni content reach nanometer range after milling 20 h, moreover, the grain size decreases and microstrain increases with prolonging milling time.