Al-C在机械合金化过程中的结构变化

Structural evolution of Al-C mixture during mechanical alloying

针对C原子的扩散过程,研究了Al-石墨在机械合金化过程中的结构变化.用X射线衍射仪(XRD)、扫描电子显微镜、拉曼光谱仪及计算机模拟观察,分析了不同球磨时间的Al-C混合物的结构.结果表明,球磨初期,石墨晶粒尺寸的减小及六角石墨转变为Turbostratic结构,使石墨的X射线衍射峰迅速减弱,以至消失.随球磨时间的增加,C原子逐渐扩散到Al的点阵中形成固溶体.将Al-C固溶体进行退火处理,便转变为Al4C3.即使在球磨产物的XRD图中观察不到石墨的衍射峰后,继续球磨数十小时,拉曼光谱表明球磨样品中仍有未与Al反应的单质石墨.

Aimed at the diffusion process of C atoms, the structural evolution of Al-C mixture during mechanical alloying was studied. By using X-ray diffraction （XRD）, scanning electron microscopy （SEM）, Raman spectroscopy and computer simulation, the structure of A1-C mixture milled for different hours was characterized. Experimental results show that the decreased grain size of graphite and the transformation from hexagonal graphite to Turhostratic structure make the diffraction peaks of graphite decrease rapidly, even disappear in the initial stage of milling. C atoms diffuse into Al lattice, and an Al-C solid solution is formed during further milling. The Al-C solid solution transforms into Al4C3 during annealing. Raman spectra confirm that elemental graphite still exists in the samples further milled for several tens of hours after the diffraction peaks of graphite has completely disappeared in the XRD patterns of the milled product.