固液相区等温保温时A356铝合金半固态初生相形貌演变特征  

Evolution Characteristics of Semi-solid Primary Phase in A356 Al Alloy During Isothermal Holding in Solid-liquid Phase Region

作　　者：刘政[1] 于锋波[1] 

机构地区：[1]江西理工大学材料与化学工程学院,江西赣州341000

出　　处：《热加工工艺》2008年第1期6-9,共4页Hot Working Technology

基　　金：江西省自然科学基金资助项目(0650047)

摘　　要：在615～595℃不同温度下对A356合金液保温1min和在600℃保温1～10min,研究了A356半固态初生相在不同保温温度和保温时间下的组织形貌演变特征。结果表明:在不同的保温温度下,随着保温温度的降低,枝晶组织向蔷薇状和颗粒状组织演变;在相同的保温温度不同的保温时间下,随着保温温度的延长,其初生α-Al的圆形度逐渐变好,但颗粒的大小有先减小后长大的趋势,600℃保温5min的效果最好;保温的过程由于原子扩散及能量起伏等,合金会发生成分均匀化,消除或大大减小成分过冷,有利于形成球状和颗粒状组织。Holding time 1 min at 615-595 ℃ and isothermal holding at 600 ℃ about 1 -10 min for A356 Al alloy, the evolution characteristics of semi-solid primary phase about A356 Al alloy at different isothermal holding temperatures and time were investigated. The results show that the microstructure changes from dendritic to rosette, and then to spherical grains, as the holding temperature falls. In addition, the rotundity degree of primary phase α-Al is better and better with protracting of the holding time, the best holding time is 5 min at 600 ℃. In virtue of atom diffusing and energy fluctuation during holding temperatures, the component of the alloy becomes uniformity and minishes the constitutional tmdercooling, therefore this can cause the spherical primary α-Al grains formed in the end of solidification.

关 键 词：A356铝合金 半固态 初生相形貌 演变特征 

分 类 号：TG146[一般工业技术—材料科学与工程] TG244[金属学及工艺—金属材料]