快速凝固法制备Mg-Al-Ca合金薄带

通过单辊快淬法制备了Mg-8.2Al-4.7Ca合金薄带,采用XRF、XRD、金相显微分析、显微硬度测量等分析方法研究了其凝固组织及相结构,以及转速对镁合金条带厚度和显微硬度的影响。研究结果表明,急冷快速凝固条件下,合金形成非晶相 细小hcp-Mg(Al,Ca)相;镁合金薄带显微组织沿厚度方向分为近辊面细晶区、内部柱状晶和自由面粗晶区;随着辊速的提高,晶粒不断细化,薄带的硬度不断提高。晶粒细化是显微硬度提高的主要原因。

Preparation of Mg-Al-Ca Ribbons by Melt-spinning

The solidification structure and phase constituent of Mg-8.2Al-4.7Ca alloy ribbons prepared by melt-spinning have been observed by XRF,XRD, optical observation and micro-hardness measurements, meanwhile, the effects of rotating speed of the single-roller on the thickness and micro-hardness of the Mg alloy ribbons have been approached. The results indicate that the melt-spinning alloy ribbons are composed of amorphous phase and fine hcp-Mg(Al,Ca) phase, which is different from that of conventionally solidified alloy ribbons. It can be observed from the cross section of the ribbon that three distinct zones appears in the microstructure: fine equiaxed grain size close to the copper roller, columnar zone and coarse equiaxed grain zone close to the free surface. With the increase of rolling speed, the micro-hardness of the alloy ribbons can be increased, which is attributed to the refinement of the grain size.