论文部分内容阅读
采用差式扫描热量法、光学显微镜和扫描电镜研究机械滚筒流变处理下ADC12铝合金的初生相演变。半固态浆料分析表明:合金的固相率随着滚筒转速的提高从0.38增加到0.43,但圆整度从0.45降低到0.38。随着浇注温度从620°C降到580°C,合金固相率和初生相平均颗粒尺寸随着浇注温度的下降而增加,初生相形貌由近球形转变为玫瑰形。在流变压铸条件下,合金中初生相α(Al)颗粒形貌圆整、颗粒细小并分布均匀。在595和605°C之间进行流变压铸可以获得最佳的显微组织。晶粒控制生长理论是ADC12铝合金实现流变处理的理论依据,半固态浆料在压铸成型中服从Mullins-Sekerka准则。
Differential scanning calorimetry, optical microscopy and scanning electron microscopy were used to study the primary phase evolution of ADC12 aluminum alloy under the condition of mechanical roller rheology. Semi-solid slurry analysis showed that the solid fraction of the alloy increased from 0.38 to 0.43 with the increase of rotating speed, but the roundness decreased from 0.45 to 0.38. As the pouring temperature dropped from 620 ° C to 580 ° C, the solid fraction of the alloy and the average primary particle size increased with the decrease of the pouring temperature, and the morphology of the primary phase changed from nearly spherical to rose-shaped. In the condition of rheo-diecasting, the morphology of primary α (Al) particles in the alloy is round and the particles are fine and evenly distributed. Rheology die-casting between 595 and 605 ° C gives the best microstructure. The theory of grain-controlled growth is the theoretical basis for rheological treatment of ADC12 aluminum alloy. Semi-solid slurry obeys Mullins-Sekerka criterion in die-casting.