超声外场对AlTiC细化剂中TiC粒子过冷形核的影响  

Effect of ultrasonic field on undercooling nucleation of Ti C particles in AlTiC refiner

作　　者：宁佳杰 李晓谦[1] 董方[1] 黄明哲[1] 

机构地区：[1]中南大学机电工程学院高性能复杂制造国家重点实验室,长沙410083

出　　处：《粉末冶金材料科学与工程》2015年第1期19-25,共7页Materials Science and Engineering of Powder Metallurgy

基　　金：国家重点基础研究发展规划(973计划)资助项目(2010CB731706;2012CB619504)

摘　　要：在7085铝合金凝固过程中添加质量分数为5%的Al-5Ti-0.2C细化剂,并施加超声外场,运用EPMA、SEM检测超声外场对铝合金溶质元素分布的影响,对比其铸锭凝固组织,探讨超声外场对AlTiC细化剂细化率的影响。研究结果表明:添加AlTiC细化剂的细化率为44.7%,再施加超声外场,细化率可再提高31.4%;EPMA元素面扫描结果表明,施加超声后Ti元素和C元素在晶界的聚集明显减少;SEM元素线扫描结果表明,施加超声外场使Zn、Mg、Cu主要溶质元素相对均匀地分布在铝熔体中;施加超声外场后,TiC粒子形核的成分过冷度增大并且过冷度局部差异减小,有利于形成均匀细小的等轴晶组织。0.5%（mass fraction） Al-5Ti-0.2C refiner was added during the solidification of 7085 aluminum alloy, and ultrasonic filed was applied, the microstructures of ingots with different working conditions were compared. Using EPMA and SEM to investigate the effect of ultrasonic field on the aluminum alloy solute elements distribution, the influence of ultrasonic field on Al Ti C grain refinement rate was investigated. The results show that the refinement rate is 44.7% when adding Al Ti C refiner, and the refinement rate is 76.1% when adding both Al Ti C refiner and ultrasonic field, which means applying ultrasound increases refinement rate by 31.4%. EPMA element surface scanning results show that after applying ultrasonic Ti and C elements are relatively evenly distributed inside the crystal, concentrations of Ti and C elements in the grain boundary decrease significantly. SEM element line scan results show that applying ultrasound makes Zn, Mg, Cu solute elements distributed relatively evenly in the aluminum melt, the constitutional undercooling degree of Ti C particles increases and local variations of undercooling degree decrease during nucleation, which is helpful to form a uniform fine equiaxed grain structure.

关 键 词：7085铝合金 Al-5Ti-0.2C细化剂 超声外场 过冷形核 

分 类 号：TG249.9[金属学及工艺—铸造] TB559[理学—物理]