不同Ni含量铁基激光熔覆层组织和性能的研究

发布时间：2019-01-25 08:59

【摘要】：目的研究不同Ni含量铁基激光熔覆层的组织和性能。方法采用CO_2激光器制备了不同Ni含量的铁基激光熔覆层,通过奥林巴斯光学显微镜、场发射扫描电镜、X射线衍射仪及洛氏硬度计等设备,对激光熔覆层物相、微观组织及力学性能进行表征。结果当Ni含量为10%~11%时,熔覆层物相主要由γ-Fe相组成,含有少量α-Fe相,洛氏硬度为35.1HRC,熔覆层残余应力宏观上表现为拉应力。当Ni含量为6%~7%时,熔覆层物相主要由α-Fe相组成,含有少量γ-Fe相,洛氏硬度为47.9HRC,熔覆层残余应力宏观上接近平衡状态。当Ni含量为2%~3%时,熔覆层主要由α-Fe相组成,洛氏硬度为60.3HRC,熔覆层残余应力宏观上表现为压应力。结论不同Ni含量熔覆层的物相主要由γ-Fe相和α-Fe相组成,随着Ni含量的降低,熔覆层中γ-Fe相对应的衍射峰强度不断减弱,而α-Fe相对应的衍射峰强度逐渐增强,熔覆层晶粒尺寸减小,表面洛氏硬度增加,残余应力逐渐由拉应力转变为压应力,能够有效抑制裂纹的生成,从而获得高硬度不开裂熔覆层。
[Abstract]:Objective to study the microstructure and properties of iron based laser cladding coating with different Ni content. Methods the Fe-based laser cladding layer with different Ni content was prepared by CO_2 laser. The laser cladding phase was prepared by Olympus optical microscope, field emission scanning electron microscope, X-ray diffractometer and Rockwell hardness tester. Microstructure and mechanical properties were characterized. Results when the content of Ni was 10 ~ 11, the phase of the cladding was mainly composed of 纬-Fe phase, containing a small amount of 伪-Fe phase, and the Rockwell hardness was 35.1HRC. The residual stress of the cladding layer showed tensile stress macroscopically. When the content of Ni is 6 ~ 7, the phase of the cladding layer is mainly composed of 伪-Fe phase, containing a small amount of 纬-Fe phase, and the Rockwell hardness is 47.9 HRC. The residual stress of the cladding layer is close to equilibrium state macroscopically. When the Ni content is 2 ~ 3, the cladding layer is mainly composed of 伪-Fe phase, and the Rockwell hardness is 60.3 HRC. The residual stress of the cladding layer appears to be compressive stress macroscopically. Conclusion the phase of the cladding layer with different Ni content is mainly composed of 纬-Fe phase and 伪-Fe phase. With the decrease of Ni content, the diffraction peak intensity of 纬-Fe phase in the cladding layer decreases continuously, while the diffraction peak intensity corresponding to 伪-Fe phase increases gradually. The grain size of the cladding layer decreases, the surface hardness increases, and the residual stress gradually changes from tensile stress to compressive stress, which can effectively inhibit the formation of cracks and thus obtain the high hardness non-cracking cladding layer.
【作者单位】：南华大学机械工程学院;
【基金】：国家自然科学基金项目(51474130) 湖南省市联合基金重点项目(13JJ8013) 湖南省高校重点实验室项目(湘财教指[2014]85号) 湖南省重点学科建设项目(湘教发[2011]76号) 湖南省高校科技创新团队支持计划(湘教通[2012]318号)~~
【分类号】：TG174.4

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