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针对装备零部件表面疲劳失效的问题,开发了一种能够在堆焊修复层表面制备纳米晶粒的预压力滚压技术,分析了该技术的设备特点和基本工作原理,利用场发射扫描电镜、高分辨透射电镜和纳米压痕仪对堆焊层表面纳米晶层微观结构及力学性能进行了分析。结果表明:滚压加工后,零件表面形成明显的塑性变形层,其中严重塑性变形层厚度约为15μm;最表层形成了细化均匀的纳米晶层,平均晶粒尺寸约为10 nm;表面硬度提高了3倍。该技术能够有效地细化表面晶粒,达到优化金属零件表面结构的目的。
Aiming at the problem of surface fatigue failure of equipment parts, a pre-press rolling technology capable of preparing nanocrystalline grains on the surface of the repaired layer was developed. The equipment characteristics and basic working principle of the equipment were analyzed. By using field emission scanning electron microscope, The microstructure and mechanical properties of the nanocrystalline layer on the surfacing layer were analyzed by high resolution transmission electron microscopy and nano indenter. The results show that the plastic deformation layer is formed on the surface of the part after rolling. The thickness of the serious plastic deformation layer is about 15μm. The thinnest uniform nanocrystalline layer is formed on the outermost surface with an average grain size of about 10 nm. The surface hardness Increased by 3 times. The technology can effectively refine the surface grain, to achieve the purpose of optimizing the surface structure of metal parts.