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利用XRD和XAFS方法研究机械合金化Fe70 Cu30 二元金属合金随球磨时间的结构变化 .XRD结果表明 ,球磨 2h后 ,部分金属Fe与Cu生成Fe Cu合金 ;球磨 2 0h后 ,金属Fe与Cu已完全合金化生成Fe -Cu合金 ,并只在 2θ =4 4°处出现一个宽化的弱衍射峰 ,认为是在球磨 2 0h后的Fe70 Cu30 合金中共存着fcc和bcc结构的Fe -Cu合金相 .XAFS结果进一步表明 ,在球磨的初始阶段 (2h) ,fcc结构的Cu颗粒的晶格产生较大的畸变 ,其无序度σ(σ =σT+σS)为 0 0 190nm .球磨 5h后 ,部分fcc结构的Cu原子进入了无序度相对较小的bcc结构的α -Fe相 ,导致Cu原子的平均无序度σ降为 0 0 10 8nm .球磨 10h后 ,样品中很大比例的Fe原子处于fcc结构的Fe -Cu合金相 ,其无序度为σ =0 0 119nm ;而大部分Cu原子依然保持fcc结构 ,无序度为σ =0 0 110nm .这是由于扩散到bcc结构α -Fe相的Cu原子超过某一浓度后 (约 30 %— 4 0 % ) ,Cu原子能诱导其产生fcc结构相变所致 .球磨时间增加到 2 0h ,样品中Cu原子和Fe原子在fcc和bcc相的比例与球磨 10h基本相同 ,生成的Fe -Cu合金混合相的组成和结构分别近似于bcc结构的Fe80 Cu2 0 和fcc结构的Fe6 0 Cu4 0 .
XRD and XAFS methods were used to study the structural changes of mechanical alloying Fe70 Cu30 binary metal alloys with milling time.XRD results showed that some metals Fe and Cu generated Fe Cu alloy after ball milling for 2h, Completely alloyed to form Fe-Cu alloy and showed only a broad diffraction peak at 2θ = 4 4 °. It is considered that Fe-Cu alloy with fcc and bcc coexist in Fe70 Cu30 alloy after ball milling for 20 h Phase XAFS results further show that the lattice of fcc Cu lattice has a large distortion in the initial stage of ball milling (2h), and its degree of disorder σ (σ = σT + σS) is 0 0 190nm. After milling for 5h , Part of the fcc structure of Cu atoms into a relatively small degree of disorder bcc α -Fe phase, resulting in the average degree of Cu atoms σ decreased to 0 0 10 8nm. After milling 10h, a large proportion of samples Fe atoms are in the fcc structure of Fe-Cu alloy phase, the degree of disorder is σ = 0 0 119nm; and most of the Cu atoms still maintain the fcc structure, the degree of disorder is σ = 0 0 110nm. This is due to diffusion to the bcc structure After the Cu atom of the α-Fe phase exceeds a certain concentration (about 30% to 40%), the Cu atom can induce its generation of fcc Phase transformation caused by milling time increased to 20h, the sample Cu atoms and Fe atoms in the ratio of fcc and bcc phase and ball milling 10h basically the same, the resulting Fe-Cu alloy mixed phase composition and structure were similar to the bcc structure Of Fe80 Cu2 0 and fcc of Fe6 0 Cu4 0.