B/Zr摩尔比对Al-Zr-B合金的组织和晶粒细化效果的影响  

Microstructure and Grain Refinement of Al-Zr-B Alloy with Different B/Zr Mole Ratios

作　　者：钟芳华[1,2] 戚文军 王顺成 周海涛[2] 陈学敏 彭谦之[2] 

机构地区：[1]广东省工业技术研究院金属加工与成型技术研究所,广东广州510650 [2]中南大学材料科学与工程学院,湖南长沙410083 [3]新星化工冶金材料(深圳)有限公司,广东深圳518106

出　　处：《稀有金属》2014年第2期193-201,共9页Chinese Journal of Rare Metals

基　　金：国家科技部高技术研究发展计划(863计划)(2013AA031001);广东省教育部产学研结合项目(2010A090200078;2012B090600051)资助

摘　　要：以Al,K2ZrF6和KBF4为原料,采用熔体反应法制备不同B/Zr摩尔比Al-Zr-B合金。利用光学显微镜(OM)、扫描电子显微镜(SEM)、X射线衍射分析(XRD)等手段研究了B/Zr摩尔比对Al-Zr-B中间合金的组织和晶粒细化效果的影响。结果表明,随着B/Zr摩尔比的增加,Al-Zr-B中间合金的第二相组成发生改变。当B/Zr摩尔比为1时,第二相主要由粗大的块状ZrAl3相及少量团聚在晶界上的ZrB2粒子组成;当B/Zr摩尔比为2时,第二相为ZrB2粒子和少量块状ZrAl3相。当B/Zr摩尔比为3时,第二相全部为ZrB2粒子。对AZ91D合金的细化实验表明,随着B/Zr摩尔比的增加,晶粒细化效果越好,添加B/Zr摩尔比为3的Al-Zr-B中间合金具有明显的细化效果,合金由粗大的树枝晶转变成细小的等轴晶,固溶处理后的AZ91D合金平均晶粒尺寸由约328μm下降到约120μm;抗拉强度和延伸率达到213 MPa和4.95%,比未添加细化剂时分别提高了15.1%和30.3%。晶粒细化机制可归结为ZrB2粒子作为α-Mg的异质形核核心。AThe Al-Zr-B master alloys with different B/Zr mole ratios were prepared by the direct melt reaction method with AI, K2ZrF6 powder and KBF4 powder as raw materials. The influence of B/Zr ratio on the microstrueture and grain refinement of Al-Zr-B master alloy was investigated by optical microscope （OM）, scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The results showed that the formation of the secondary phases in Al-Zr-B alloy firmly depended on the B/Zr mole ratio. The secondary pha- ses were mainly composed of ZrAl3 which was coarse and massive, and ZrB2 particles which were easy to join together to form some par- ticle clusters and distribute along the α（Al） grain boundary when the B/Zr mole ratio was about 1. The secondary phases were mainly composed of ZrB2 particles and a few ZrAl3 phases when the B/Zr mole ratio was about 2. All the secondary phases were ZrB2 particles when the B/Zr mole ratio was about 3. The refining experiment showed that the refining effect became better with the increase of B/Zr mole ratio, the Al-Zr-B master alloy with a B/Zr mole ratio of 3 had a desirable refining effect, which led the coarse dendrite to small equiaxial grains. After solid solution treatment on AZ91D alloy, the average grain sizes could be refined from 328 to 120 p.m, and its tensile strength and elongation were 213 MPa and 4. 95%, respectively, which were increased by 15.1% and 30.3% compared with the AZ91 D alloy without addition of Al-Zr-B master alloy. The mechanism of grain refinement was ascribed to the ZrB2 particles acting as the heterogeneous nucleus of primary α-Mg phase.

关 键 词：Al-Zr-B中间合金 B Zr摩尔比 镁合金 晶粒细化 

分 类 号：TG146.22[一般工业技术—材料科学与工程]