TiB的添加对ZnAl合金改性的微观影响  

Microstructural role of TiB addition in modifying ZnAl alloy

作　　者：周玉琳 宋文豪 赖玉香 陈江华 Yu-lin ZHOU;Wen-hao SONG;Yu-xiang LAI;Jiang-hua CHEN(Center for High-Resolution Electron Microscopy,College of Materials Science and Engineering,Hunan University,Changsha 410082,China;Hunan Nonferrous Metals Holding Group Co.,Ltd.,Changsha 410015,China;Pico Electron Microscopy Center,Hainan University,Haikou 570228,China)

机构地区：[1]湖南大学材料科学与工程学院高分辨电镜中心,长沙410082 [2]湖南有色金属控股集团有限公司,长沙410015 [3]海南大学皮米电镜中心,海口570228

出　　处：《Transactions of Nonferrous Metals Society of China》2023年第9期2726-2739,共14页中国有色金属学报（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(Nos.52001119,51831004,52171006);the Fundamental Research Funds for the Central Universities,China.

摘　　要：采用扫描电子显微镜、高角度环形暗场扫描透射电子显微镜和能量X射线谱,研究TiB的加入对锌铝共晶(ZA27)合金改性的微观作用。铸造一系列Zn−27Al−2Cu−0.02Mg−x(Ti+B)(x=0,0.01,0.02,0.05,0.10,0.20,质量分数,%)合金。研究结果表明,ZA27合金的硬度和强度随(Ti+B)含量的增加而提高,在(Ti+B)含量为0.05%时达到最高值。TiB改性剂可以细化初生α(Al)相晶粒,改变珊瑚状(α(Al)+η-Zn)共析组织的微观结构,这是ZA27合金力学性能提高的原因。改性后的共析组织表现出篮状和条状共析组织微观结构特点。初生α(Al)相晶粒的细化很可能与B在固−液界面上偏析引起的成分过冷有关。B和/或Ti参与共晶和共析反应,改变了共析组织的形态。The microstructural role of TiB addition in modifying a Zn−Al eutectoid(ZA27)alloy was investigated using scanning electron microscopy,high-angle annular dark-field scanning transmission electron microscopy,and energy X-ray spectroscopy.A series of Zn−27Al−2Cu−0.02Mg−x(Ti+B)(x=0,0.01,0.02,0.05,0.10,0.20,wt.%)alloys were cast.The results show that the hardness and strength of the ZA27 alloy are improved with increasing(Ti+B)content,and peak at a(Ti+B)content of 0.05 wt.%.The TiB modifier refines the primaryα(Al)phase grains and changes the microstructure of coralloid(α(Al)+η-Zn)eutectoid,which is responsible for the increased mechanical properties of the ZA27 alloy.The modified eutectoid demonstrates featured basket-like and strip-like eutectoid microstructures.The refinement of the primaryα(Al)phase grains is very likely related to the constitutional supercooling caused by the segregation of B at the solid−liquid interface.Participation of B and/or Ti in the eutectic and eutectoid reactions modifies the morphology of the eutectoid microstructure.

关 键 词：Zn−Al合金 TiB改性剂 显微组织 力学性能 电子显微术 

分 类 号：TG146.13[一般工业技术—材料科学与工程]