摘要
在前期Al_2Y/AZ91镁基复合材料流变性能的研究基础上,将建立的Al_2Y/AZ91镁基复合材料表观粘度模型导入模拟软件,对Al_2Y/AZ91镁基复合材料液态及半固态充型及凝固过程进行了模拟,对压力场、速度场、固相分布和成形过程的缺陷进行了分析,结果表明,液态充型压力分布比较紊乱,熔体的流态为紊流,在型腔中容易产生涡流现象,在凝固过程中,铸件内部的冷却速度不一致,后续凝固的涡流区域在凝固过程中得不到有效的金属液的补充,进而容易产生缩孔缩松。半固态充型过程熔体内部压力传递相对比较平稳,速度分布均匀,熔体的流态表现为层流,不会产生涡流,铸件内外凝固速度相差不大,在整个凝固过程中不容易产生缩孔缩松等缺陷。为了验证模拟结果的正确性,进行了复合材料的流变成形实验,由实验可知,流变成形铸件显微组织以球状晶为主,没有孔洞缺陷,铸件成形质量较好。实验结果与模拟结果较吻合。
Based on the previous study of the rheological properties of Al_2Y / AZ91 magnesium matrix composites,putting the Al_2Y /AZ91 magnesium matrix composites apparent viscosity model into the simulation software,the liquid and semi-solid filling and solidification process of Al_2Y / AZ91 magnesium matrix composites were simulated by simulation software. The pressure field,velocity field,solid distribution of solidification process and defects of forming process were analyzed. As the results showed,during the liquid filling process the distribution of pressure was inordinate,the melt flow was turbulent,and eddy current phenomenon was easy to produce in the mold cavity,due to the inconsistency of the internal cooling rate of the casting during the solidification process; the subsequent solidified eddy zone could not be filled effectively by metal liquid,and shrinkage cavity and porosity were produced during the solidification process. During the semi-solid filling process,the pressure transfer was relatively stable,the melt flow was laminar flow,velocity distribution was uniform,no eddy current phenomenon occurred,the solidification velocity of inside of casting had little difference from the solidification velocity of outside of casting,and no shrinkage cavity and porosity occurred during the solidification process. In order to verify the correctness of the simulation results,the rheological forming experiment was carried out. As the results showed,a large number of spherical grains were distributed in the microstructure of the rheological forming casting,and the casting quality was better with no cavity defect. The experimental results were in accordance with the simulation results.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2016年第8期776-783,共8页
Chinese Journal of Rare Metals
基金
国家自然科学基金项目(51165032)
江西省研究生创新基金项目(355906310011)资助
关键词
镁基复合材料
半固态
流变成形
数值模拟
magnesium matrix composites
semi-solid
rheoforming
numerical simulation
作者简介
黄文先（1975-），男，江西南昌人，博士研究生，研究方向：镁基复合材料，E-mail：huangwenxianjgs@163．com；
通信作者：闫洪，教授，电话：0791-83968873，E-mail：yanhong_wh@163．com
