H13钢表面激光选区熔覆Ni-Al金属间化合物涂层的组织与性能  

Microstructure and property of selective laser cladding Ni-Al intermetallic compound coating on H13 steel surface

作　　者：唐淑君[1] 刘洪喜[1] 张晓伟[1] 王传琦[1] 蔡川雄[1] 蒋业华[1] 

机构地区：[1]昆明理工大学材料科学与工程学院,云南昆明650093

出　　处：《红外与激光工程》2014年第5期1621-1626,共6页Infrared and Laser Engineering

基　　金：国家自然科学基金项目(61368003)

摘　　要：通过控制Ni基自熔性合金粉末中Al的含量,在H13热作模具钢表面分别原位制备了Ni3Al和NiAl金属间化合物复合熔覆涂层。借助光学显微镜和X射线衍射仪对不同熔覆涂层的化学组成和物相结构进行了分析。结果表明,四种不同Al含量的熔覆层均显现出平整致密、无明显缺陷的宏观特征。随着Al含量的增加,熔覆层显微形貌呈现出底部枝晶区域增加及枝晶逐渐粗化,甚至出现胞状晶的现象。熔覆层在未加入Al时,其主要物相为Ni3Fe及(Ni,Cr)固溶体。随着Al含量的增加,主要物相则由最初的Ni3Al金属间化合物、(Ni,Cr)固溶体到Ni3Al、NiAl金属间化合物和(Fe,Cr)固溶体,再到最终Al含量达到13.9%时的NiAl金属间化合物和(Fe,Cr)固溶体。同时,Al含量的提高使得涂层中杂质相减少。熔覆层摩擦系数均低于基体,最高显微硬度为基体的3.5倍,耐磨性较基体提高了5.8倍。In situ Ni3Al and NiAl intermetallic compound composite laser cladding coatings were prepared on H13 hot die steel surface by controlling Al content in the Ni- based self- fluxing alloy powder. The chemical composition and phase structure of the different laser cladding composite coatings were characterized by optical microscopy （OM） and X- ray diffraction （XRD）. The results indicate that the four kinds of composite laser cladding coatings all show a smooth, dense and without obvious defects macroscopic morphology. The dendrite region becomes wider and the dendrite size gradually becomes thicker in the laser cladding coatings bottom with the increase of Al content, even a columnar crystal phenomenon can be found. Without Al, the main phase of the composite coating is Ni3Fe and Ni- Cr solid solution. While with the increase of Al content, the main phase changes from Ni3Al intermetallic compound and Ni- Cr solid solution to Ni3Al＋NiAl intermetallic compound and Fe- Cr solid solution, and then to NiAl intermetallic compound and Fe- Cr solid, when the Al content increases to 13.9%. At the same time, the impurity phase in laser cladding coating decreases with the increase of the Al content. The cladding coatings friction coefficients are lower than those of the H13 steel substrate. The highest microhardness of the coating increases by 250% and the abrasion resistance increases by 480%respectively.

关 键 词：激光熔覆 H13钢 复合涂层 金属间化合物 显微组织 

分 类 号：O436[机械工程—光学工程]