堆焊层预压力滚压表面纳米化层的微观结构  

Microstructure of surface nanocrystalline layer on the surfacing layer induced by pre-load rolling

作　　者：巴德玛[1] 孟凡军[1] 孙晓峰[1] 刘晓亭[1] 李新[2] 

机构地区：[1]装甲兵工程学院装备再制造工程系,北京100072 [2]北京特种车辆研究所,北京100072

出　　处：《材料热处理学报》2015年第1期173-177,共5页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51105376);再制造国防科技重点实验室基金(9140c850403130c85009)

摘　　要：利用场发射扫描电镜、高分辨透射电镜和表面三维形貌仪对经预压力滚压表面纳米化处理的堆焊层的表面微观结构进行研究。结果表明,用中锰焊丝在Cr-Ni合金钢表面制备堆焊层,经滚压加工后,零件表面粗糙度明显降低,零件表面层形成厚度约10μm的明显塑性变形层;在最表层形成了平均晶粒尺寸约10 nm的具有随机取向的等轴晶,纳米晶粒的尺寸随距表面距离增加而增大;在距表面为10~15μm处,存在平均晶粒尺寸约100 nm的等轴晶和具有相近尺寸的胞状结构。预压力滚压加工在提高表面光洁度同时,能够有效地将堆焊层的树枝状晶细化为纳米晶。The microstructure of the nanocrystalline surface layer fabricated on the surfacing layer by pre-load rolling technology( PLRT)was characterized by using scanning electron microscopy,high resolution transmission electron microscopy and 3-D topography instrument.A surfacing layer was prepared on the chrome-nickel alloy steel surface by using the medium manganese surfacing wire. Experimental results show that the roughness of surfacing layer is significantly reduced,the obvious plastic deformation layer is observed,the thickness of deformation layer is about 10 μm. A nanocrystalline surface layer is found on the surfacing layer after PLRT treatment. The grain size of equiaxed nanocrystallines with random crystallographic orientations on the top surface layer is about 10 nm. The grain size increases gradually with the increasing distance from the top surface layer. In the region about 15 μm deep from the top surface,the microstructure is mainly composed of 100 nm roughly equiaxed grains and subgrains. The coarse crystal in the surfacing layer can be refined into nanocrystalline while reducing roughness by using the pre-load rolling technology.

关 键 词：滚压技术 表面纳米化 堆焊层 微观结构 

分 类 号：TG455[金属学及工艺—焊接]