(中南大学 材料科学与工程学院，长沙 410083)
摘 要: 采用光学显微镜和扫描电镜等检测手段研究喷射沉积Al-27%Si合金二次加热的显微组织及其转变规律。在二次加热过程中，喷射沉积Al-27%Si合金的组织转变经历3个阶段：转变初期，试样中液相体积分数很少，Si相在晶界长大；转变中期，试样中液相体积分数不断增大，α(Al)相与Si相熔化；转变后期，α(Al)相消失，合金中Si相和液相两相平衡，液相与Si相的体积分数不变，Si相尺寸却随之增大。二次加热温度越高，每个转变阶段的时间越短，随着二次加热的进行，合金中的Si相形貌逐渐由近球形转变为板条形。
关键字: Al-27%Si合金；二次加热；半固态成形；喷射沉积；α(Al)相；Si相
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The microstructures of spray-deposited Al-27%Si alloy and their evolutions at different re-heating temperatures were studied by optical microscopy (OM) and scanning electron microscopy (SEM). During the re-heating treatment of spray-deposited Al-27%Si alloy, Si phases coarsen at the grain boundaries, then the volume fraction of liquid phase increases with the re-melting of α(Al) phase and Si phase, and finally achieves the equilibrium of Si phase and liquid phase, the volume fractions of Si phase and liquid phase keep constant, but the dimension of Si phase increases with the decrease of Si particle number. With the temperature increase of the re-heating treatment, the transformation time of each transition stage decreases. The shapes of Si phases convert from near-spherical to the lamellae during the re-heating treatment.
Key words: Al-27%Si alloy; re-heating treatment; semi-solid forming; spray depositing; α(Al) phase; Si phase
