摘要
研究了ZL112Y压铸铝合金在半固态压铸成形过程中的组织演变过程。观察了原始料坯、半固态重熔后快速水淬的料坯、压铸机压室内的冲头料坯以及压铸模内的内浇口和半固态压铸零件中不同部位的固相α组织的形貌,同时采用定量金相的方法分析了这些部位的固相α组织的圆形度、粒子平均直径和单位面积粒子个数等参数。结果表明:半固态重熔过程使原始料坯中的α枝晶组织变成节杆状和球团状组织,转变的原因是枝晶熔断机制;重熔后料坯在压室内的运动过程使半固态料坯中的α粒子尺寸的不均匀性得以消除,同时使残留的枝晶得以进一步的分离细化;α相均匀化和细化了的半固态浆料进入铸型后液相更容易到达铸件远端,液相和固相充型是2个不同的过程,液相的充型速率要大于固相。
Structural evolutions of ZL112Y die cast alloy in procedures of semisolid diecasting were investigated. The structures of solid α phase of original billet, semisolid remelting billet after quenching in water, pierce block in the chamber of diecasting machine, ingate block in die cast mould and specimens at different locations in a semisolid die cast component were observed. Meanwhile, the circularity of α particles, mean equivalent diameter of α particle, volume fraction of α solid phase, numbers of α particles were measured by the quantity analysis of metallography. The results show that, 1)dendritical colonies of α phase in original billet change into isolated grains with forms of nodules and granule, owing to the dendrite fusingoff mechanism of alloys at heating up to semisolid temperatures, and the semisolid billet has a thixotropy property and can be used to form component in die casting; 2)the motion of the billet in squeezing chamber in die cast machine minimizes heterogeneity of sizes of α particles and refines dendrites further that are remained during semisolid remelting; and 3)liquid phase more easily arrives at the end of the component than solid α particle as homogenized and refined semisolid slurry enters the cavity of diecasting mould, therefore, in the location in a component far from ingate the number of solid α particles is less than that near ingate.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2003年第4期956-962,共7页
The Chinese Journal of Nonferrous Metals
关键词
组织演变
半固态压铸
压铸铝合金
半固态成形
structural evolution
semi-solid die-casting
ZL112Y die cast aluminium alloy
