凝固速度对Ni47Ti44Nb9铸态合金组织和织构的影响  

Influence of Solidification Rate on Microstructure and Texture of Ni_(47)Ti_(44)Nb_9 Cast Alloy

作　　者：孙明艳[1] 孟玉堂[1] 张永皞[1] 范啟 超 王英英[1] 李敬民[1] 黄姝珂[1] Sun Mingyan, Meng Yutang, Zhang Yonghao, Fan Qichao, Wang Yingying, Li Jingmin, Huang Shuke(China Academy of Engineering Physics, Mianyang 621900, China)

机构地区：[1]中国工程物理研究院,四川绵阳621900

出　　处：《稀有金属材料与工程》2018年第10期3185-3190,共6页Rare Metal Materials and Engineering

基　　金：中国工程物理研究院科学技术发展基金(2015B0302060)

摘　　要：对比研究了Ni_(47)Ti_(44)Nb_9合金快冷铸锭和慢冷铸锭的宏、微观组织和织构特点,分析了凝固速度对组织和织构的影响机理。采用光学显微镜(OM)和扫描电子显微镜(SEM)观察了微观组织,采用X射线衍射(XRD)分析了织构。结果表明,铸态Ni_(47)Ti_(44)Nb_9合金具有<113>方向的择优生长取向;凝固速度对Ni_(47)Ti_(44)Nb_9合金铸态组织和织构的形成具有重要影响,快速冷却条件下获得均匀的树枝晶组织,铸锭的横、纵截面均形成{113}<uvw>织构,慢速冷却条件下形成具有特定方向的柱状树枝晶,纵截面织构以{113}<361>、{113}<332>和{113}<141>为主;凝固过程中热量方向性传导造成的树枝晶定向生长是影响合金铸态组织和织构形成的主要原因。The microstructure and texture of the Ni47Ti44）Nb9 ingots under the conditions of fast and slow cooling were studied through optical microscope（OM）,scanning electron microscope（SEM）and X-ray diffraction（XRD）.And then the effect mechanism of the solidification rate on microstructure and texture was discussed.The results indicate that the preferred growth direction of Ni47）Ti44Nb9 cast alloy is113and there is an important effect of solidification rate on the microstructure and texture of Ni47Ti44Nb_9 cast alloy.In detail,when the cooling rate is fast,uniform dendrites with a texture of{113}uvwcan be achieved,while in the case of slow cooling,columnar dendrites with a specific direction can be obtained,and the main textures of the vertical section are{113}361,{113}332and{113}141.In addition,the directional growth of dendrites induced by directional heat conduction during the process of solidification is found to be the main reason for the formation of cast microstructure and texture.

关 键 词：形状记忆合金 NI47TI44NB9 凝固速度 织构 铸锭 

分 类 号：TG139.6[一般工业技术—材料科学与工程]