| 摘要: |
| 渗硼层高温硬度高，抗氧化性能好，但脆性大，提高渗硼层韧性是扩展实际工程应用的关键。文中在45CrNiMoV钢基体上采用电镀镍+高温扩散预处理，在表层形成γ-（Fe，Ni）层后，再用固体渗硼法制备出含镍渗硼层，并与直接渗硼层进行对比。用扫描电镜（SEM）、X射线衍射（XRD）和显微压痕法对镀镍渗硼层的截面形貌，组织结构及硬度分布和断裂韧性进行了研究。结果表明：电镀镍+扩散预处理能显著提高渗硼层的断裂韧性，淬火+低温回火热处理几乎不影响镀镍渗硼层断裂韧性，而对直接渗硼层则有显著降低。镀镍渗硼层中的γ-（Fe，Ni）相能有效缓解冲击载荷，提高渗层断裂韧性。 |
| 关键词: 电镀镍 扩散 渗硼 断裂韧性 热处理 |
| DOI：10.11933/j.issn.1007-9289.20161020001 |
| 分类号: |
| 基金项目:国家自然科学基金（51271079）；广东省自然科学基金（2015A030313223）；广东省“扬帆计划”引进创新创业团队专项资助项目（21312G02） |
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| Improvement of Fracture Toughness of Boriding Layer by Plating Nickel Layer and Diffusing Heat-treatment |
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QIU Wan-qi1, XIONG Cheng1, JIA Lei1, MO Dong-qiang2, SUN Ge2
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1.School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640;2.Huaiji Deng Yun Auto-parts(Holding) Co. Ltd., Huaiji 526400, Guangdong
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| Abstract: |
| The boriding layers have widely potential applications in tribological and antioxidation in high temperature area due to their outstanding combined properties including high-temperature hardness and chemical inertness. However, the high-brittlness of boriding layer limits its application spreading, how to improve the brittleness is the key in practical use. In this paper the nickel-boriding layers were fabricated by the powder-pack method on γ-(Fe, Ni) layer prepared by electroplating nickel and diffusing heat-treatment on 45CrNiMoV steel. The micro-hardness and the fracture toughness of the boriding layer were investigated by micro-indentation test. The cross-section morphology and phase structure were analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD). Results show that the fracture toughness of the nickel-boriding layer is improved considerably compared with that of the direct-boriding layer. The quenching and low-temperature tempering heat-treatment has scarcely effect on the fracture toughness of the nickel-boriding layer, while it greatly decreases the fracture toughness of the direct-boriding layer. The γ-(Fe, Ni) phase embedding in nickel-boriding layer can buffer the external impact power and improve the fracture toughness availably. |
| Key words: electroplated Ni diffusion boriding fracture toughness heat-treatment |
