摘要
采用近液相线半连续铸造技术,制备了120mm×1600mm的6061铝合金半固态坯料,考察了铸造温度、铸造速度和冷却强度对铸锭组织的影响。结果表明,合金熔体在常规铸造温度(720℃)下获得的铸锭组织是粗大的枝晶,且组织极不均匀;在近液相线温度(657℃)下保温后铸造的铸锭组织均匀、细小、近球形。一次冷却强度的降低、二次冷却强度的增大均有利于均匀、细小的近球形组织的形成;铸造速度达到150mm/min时可以获得细小、均匀、近球形的6061半固态坯料组织。
The semi-solid 6061 aluminum alloy billets with 120 mm in diameters and 1600 mm in length were prepared by near-liquidus semi-continuously casting.Effects of pouring temperature,pulling velocity and cooling rate on microstructure of the ingot were analyzed.The results indicate that the microstructure of ingot poured at 720 ℃ exhibits coarse dendrite with heterogeneous distribution,while that of poured at 657 ℃ exhibits homogeneous fine near-globular structure.The uniform and fine near-globular structure in the ingot can be easily formed with decreasing in firstly cooling rate and then increasing in cooling rate.In addition,the semi-solid 6061 aluminum alloy billets with uniformly fine near-globular structure can be observed with casting velocity of 150 mm/min.Near-liquidus semi-continuously casting is an effective method for preparing 6061 aluminum alloy semi-solid billets.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2009年第6期508-511,共4页
Special Casting & Nonferrous Alloys
基金
国家自然科学基金资助项目(50674032)
