摘要
基于CAFE法(元胞自动机CA-有限元FE耦合模型),借助Procast软件对水冷铜模浇铸条件下合金的三维微观组织结构进行模拟,模拟结果与实验结果一致。此外,研究了工艺参数(过热度和传热系数)以及高斯分布参数(平均过冷度、成核密度和过冷度标准方差)对合金凝固组织的影响。模拟结果表明,随着过热度的增大,柱状晶比例逐渐增大,细小柱状晶的晶粒尺寸变大,且CET(柱状晶向等轴晶转变)转化位置向合金铸件内部推移。水冷条件下(传热系数h=5000W/(m^2·K)),Ag-28Cu-2Ni合金凝固组织几乎全为柱状晶,而且晶粒粗大。空冷条件下(传热系数h=2000W/(m2·K)),柱状晶区缩小,等轴晶区占主要部分。缓冷条件下(传热系数h=10W/(m2·K)),铸件的凝固组织几乎全为等轴晶。此外,平均过冷度越高,柱状枝晶区域越大。最大成核密度越大,晶粒尺寸越小。随着标准偏差增大,晶粒分布更加离散化,且晶粒尺寸分布更加均匀。
Based on the CAFE method(cellular automaton-finite element coupling model),the three-dimensional microstructure under the water-cooled copper mold casting conditions was simulated with the help of Procast software,the simulation results are in agreement with the experimental results.In addition,the effect of the process parameters(superheat and heat transfer coefficient)and the Gauss distribution parameters(the nucleation undercooling(ΔTv(s),max),the maximum nucleation density(nv(s),max),and the standard deviation of nucleation undercooling(ΔTv(s),σ)on the solidification structure of the alloy was also studied.The simulation results show that with the increase of superheat,the proportion of columnar crystals gradually increases,the grain size of the fine columnar crystals increases,and the CET(columnar to equiaxed transition)transformation position shifts to the interior of the alloy casting.Under the condition of water cooling(h=5 000 W/(m 2·K)),the solidification structure of Ag-28Cu-2Ni alloy is almost all columnar crystals,and the grain is coarse.Under the condition of air cooling(h=2 000 W/(m 2·K)),the columnar crystal region shrinks,and the equiaxed crystal area occupy the major part.Under the condition of slow cooling(h=10 W/(m^2·K)),the solidification structure of the casting is almost entirely equiaxed crystals.Furthermore,the higher the mean undercooling,the larger the columnar dendrite zones,and the larger the maximum nucleation density,the smaller the size of grains.The larger the standard deviation,the more discrete the grain distribution,and the more uniform the grain size distribution.
作者
方继恒
刘曦
谢明
胡洁琼
王松
张吉明
杨有才
陈永泰
王塞北
李再久
FANG Jiheng;LIU Xi;XIE Ming;HU Jieqiong;WANG Song;ZHANG Jiming;YANG Youcai;CHEN Yongtai;WANG Saibei;LI Zaijiu(Kunming Institute of Precious Metals,Kunming 650106;Department of Material Science and Engineering,Kunming University of Science and Technology,Kunming 650093)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2019年第18期3077-3084,共8页
Materials Reports
基金
国家重点基础研究发展计划项目(2017YFB0305700)
国家自然科学基金(U1602271
51707087
U1602275)
云南省重大科技项目(2018ZE011
2018ZE012
2018ZE022
2018ZE026)
云南省应用基础研究计划项目(2018FB088)~~
