Mg86.33Ni12.67Y1非晶合金的制备及其低温弛豫行为

采用单辊快速凝固技术,以4种冷却速度制备Mg86.33Ni12.67Y1非晶合金,并在Tg以下进行低温退火.利用X射线衍射(XRD)、差热分析(DTA)及扫描电镜(SEM)研究该合金的非晶形成能力、热稳定性及低温弛豫过程中的结构特征.结果表明,该非晶合金的过冷液相区宽度△Tx和约化玻璃转变温度Trg最大值分别为41.05 K和0.517 1,且随冷却速度的提高,△Tx表现出增大趋势,说明其非晶形成能力和热稳定性逐渐提高；低温退火时随退火温度逐渐升高,其非晶漫散射峰最大强度所对应的20值逐渐增大,表明原子的邻间距逐渐减小,非晶内部发生结构弛豫,导致拓扑结构不稳定性降低.

Preparation and Low Temperature Relaxation of Mg86.33 Ni 12.67 Y1 Amorphous Alloy

Mg86.33Ni12.67Y1 amorphous alloy was obtained at four cooling rates by single-roller melt-spinning technique and some samples were annealed below Tg.The glass forming ability,thermal stability and structure characteristics of the relaxation process were analyzed by X-ray diffraction(XRD),differential thermal analysis(DTA) and scanning electronmicroscope(SEM).The results show that the maximum value of the width of supercooled liquid region(ΔTx) and the reduced glass transformation temperature(Trg) are 41.05K and 0.5171,respectively,and ΔTx shows a trend of increasing gradually with the increase of cooling rate,demonstrating that the glass forming ability and thermal stability are improved;in the process of annealing,with increasing annealing temperature gradually,2θ value corresponding to the maximum intensity of the amorphous diffuse scattering peaks increases gradually,indicating the decrease of the distance between nearest neighbor atoms in clusters and the occurrence of structural relaxation in the amorphous alloy,resulting in the decrease of topological instability.