快速凝固Al-Ti-B-Sc对A356.2铝合金的晶粒细化作用  

Grain refining effect of rapid solidification Al-Ti-B-Sc on A356.2 alloy

作　　者：方正[1] 秦林[1] 丁俭[1] 赵维民[1] 

机构地区：[1]河北工业大学材料科学与工程学院,天津300130

出　　处：《河北工业大学学报》2014年第2期61-65,76,共6页Journal of Hebei University of Technology

基　　金：国家高技术研究发展计划(863计划)(2013AA031002)

摘　　要：将不同钪含量的快速凝固Al-Ti-B-Sc细化剂加入到A356.2合金中,考察细化剂对A356.2铝合金的晶粒细化效果的影响.结果表明,快速凝固Al-Ti-B-Sc细化剂能明显细化合金晶粒,经快速凝固处理的Al-Ti-B-Sc细化剂的细化效果要优于未处理的普通铸态的Al-Ti-B-Sc;而对于相同状态的细化剂,细化剂中钪的含量越高,细化效果越显著.钪元素在铝合金中可形成Al3Sc相,可增加铝合金非均匀形核的质点,起到很好的细晶作用,同时,钪元素还可以细化Al-Ti-B中的Al3Ti、TiB2等微粒,使其发挥更好的细化效果;而快速凝固技术可以促进元素分布更加均匀,也可以使细化剂中的相更加细小.综合分析,钪元素的加入和快速凝固技术的使用都会促进细化剂对A356.2铝合金的细化效果,本实验中快速凝固Al-Ti-B-0.5%Sc的细化效果最佳.当A356.2铝合金中加入0.2%快速凝固Al-Ti-B-0.5%Sc时,平均晶粒尺寸可由124.5 m细化至25.7 m,A356.2铝合金的硬度可由HV75增长至HV 96.This paper focuses on the grain refining effect of rapid solidification Al-Ti-B-Sc with different contents of scandium on A356.2 aluminum alloy. The study shows that rapid solidification Al-Ti-B-Sc can refine A356.2 aluminum alloy obviously.When the refiners with the same amount of scandium were added, rapid solidification Al-Ti-B-Sc exhibited better refining effect. At the same time, the refiner will be more effective along with the increase of scandium. When scandium was added into Al-Ti-B master alloy, Al3Sc particles formed and acted as heterogeneous nucleation. In addition, scandium can also refine the particles such as Al3Ti and TiB2 in Al-Ti-B and improve the grain refining effect. Furthermore, particles and the distributions of elements were more uniform when rapid solidification was used to prepare these refiners. Generally speaking, rapid solidification Al-Ti-B-0.5%Sc alloy possesses the best efficiency in grain refinement of the A356.2 alloy. When 0.2% Al-Ti-B-0.5%Sc alloy was added into A356.2 aluminum alloy, the average grain size ofA356.2 was decreased from 124.51am to 25.71am and the hardness value was improved from HV 75 to HV 96.

关 键 词：细化剂 A356.2合金 快速凝固 Al-Ti-B-Sc 平均晶粒尺寸 力学性能 

分 类 号：TG164.21[金属学及工艺—热处理]