电弧堆焊铁基非晶/纳米晶复合涂层的组织及性能研究

Microstructure and properties of amorphous and nanocrystalline coatings prepared by arc surfacing welding

以铁基非晶合金Fe41Co7Cr15Mo14C15B6Y2作为焊芯制备低氢型非晶堆焊焊条,利用手工电弧堆焊,调控堆焊工艺参数,在Q235钢上制备两种不同非晶/纳米晶组分的复合堆焊层.利用XRD/SEM/TEM探索不同堆焊工艺下的结构组织演变及非晶/纳米晶的组成比例变化,研究了不同比例非晶/纳米晶复合堆焊层的晶化特征、硬度和耐磨性变化.实验结果表明,堆焊层为铁基非晶/纳米晶复合涂层,与基体达到了良好的冶金结合；涂层中非晶相含量最高可达47．44％,纳米晶粒尺寸为10～48nm,堆焊层的最高硬度达1226HV1,其耐磨性可达Q235钢的8倍；两组堆焊层的晶化激活能分别为Ex（150A）＝107．476kJ/mol, Ex（160A）＝58．104kJ/mol；随着堆焊热输入的增加,堆焊层中非晶相的含量降低,纳米晶粒尺寸增大,堆焊层的晶化温度、热稳定性、硬度和耐磨性有所降低.

A kind of surfacing welding electrode with iron-based amorphous alloy Fe41Co7Cr15Mo14C15B6Y2 weld core and low hydrogen coating was welded on the surface of Q235 steel to obtain two types of amorphous/nano-crystalline coatings. Different proportions of amorphous and nanocrystalline coatings were fabricated by chan-ging the welding parameters (heat input). XRD, SEM, EDS were used to explore the structural transformations of the coatings and the proportion of nanocrystalline phases were determined;crystallization characterization, hardness and wear resistance were also studied . The experiments results present that the amorphous/nanocrys-talline coatings has good metallurgic bonding with the substrate, the content of amorphous phase reaches to 47. 44% and the sizes of nanocrystallines are 10-50 nm, the hardness of the surfacing layer was high as 1226HV1 and the wear resistance was 8 times higher than that of Q235 steel. The crystallization activation en-ergies of the two surfacing layers are seperately Ex(150A)=107.476kJ/mol, Ex(160A)=58. 104 kJ/mol. Fur-thermore, as the heat input increase, the proportion of the amorphous phases decrease and the grain sizes of the nanocrystalline coarsen, the crystallization temperature, thermal stability, hardness and wear resistance also decrease.