摘要
液相线铸造法是获取均匀、细小非枝晶组织半固态合金浆料的一种新工艺。凝固过程的相场模拟表明,金属凝固组织形成枝晶的趋向随过冷度加大而增强,长大速度随之显著加快。液相线铸造时结晶凝固过程在枝晶形成趋向很小、长大速度较慢的过冷度范围完成,故应得到细小非枝晶组织;液相线铸造法浇注前熔体在液相线温度附近保温,发生双相区等温结晶分解过程,该过程的相场模拟显示,这一分解作用促成大量形核,导致在随后的浇注熔体中生长成大量均匀、细小非枝晶组织;二次加热至双相区,引起部分熔化和重新分解结晶,同理会使组织进一步得到改善。
Liquidus casting,a new semi-solid metal slurry making technology, was used to get uniform, fine non-dendritic structuress. It is shown through phase-field simulation of solidification that the forming tendency of dendrite and its growing rate are remarkably increased with enlarging undercooling. Under liquidus casting the solidification is performed in such a range of temperature that dendrite is harderlly formed and growing rate is slow. The phase-field simulation of isothermal decomposition of composition and phase in double phase area shows that a lot of uniform solid nuclei are able to be formed during holding of the casting melts at liquidus temperature, as a result, the fine and uniform non-dendritic structures are obtained. Seemlally, reheating at double phase area will result in the improvement of the structure through partly remelting and resolidification.
出处
《铸造》
CAS
CSCD
北大核心
2006年第5期490-493,共4页
Foundry
关键词
半固态金属
铸造组织
相场模拟
液相线铸造
semi-solid metal
microtructure
phase-field simulation
liquidus casting method
