This work investigates the potential of combining hardness gradient with surface texture （an example of bionic coupling） to improve anti-wear properties. The bionic coupling of hardness gradient and Hexagonal Textu...This work investigates the potential of combining hardness gradient with surface texture （an example of bionic coupling） to improve anti-wear properties. The bionic coupling of hardness gradient and Hexagonal Texture （HT） was achieved by laser heat treatment on steel specimens with pre-engraved hexagonal surface texture. The successful establishment of decreasing hardness from surface to internal bulk was verified by hardness measurements along the depth of cross-sectioned specimens and corre- lated with the observations from metallurgical microscopy. The tribological performance of bionic coupling specimens （HT-L） was examined under dry contact condition, together with respective control specimens of individual bionic features, e.g. HT-H （of similar surface hardness generated by conventional heat treatment but without hardness gradient） and SS-L （of smooth surface treated by the same laser processing as for HT-L）. It is found that HT-L not only exhibits lower friction coefficient and less friction fluctuation than HT-H and SS-L, but also demonstrates a 〉50% reduction of wear loss compared to HT-H and SS-L （0.0343 g for HT-L vs. 0.0723 g for HT-H, P〈0.001; 0.0343 g for HT-L vs. 0.0817 g for SS-L, P〈0.001）. Corroboratively, observations with scanning electron microscopy revealed a relatively smooth surface for worn HT-L specimen, contrasting with the rugged and grooved surfaces of worn HT-H and SS-L specimens. These results indicate that the bionic coupling of hardness gradient to hexagonal texture can indeed improve anti-wear properties, affording a new strategy to wear and friction manage- ment.展开更多
本文采用倾斜30°感应器的表面感应加热淬火工艺处理了Φ40 mm GCr15钢滚珠丝杠。金相观察和显微硬度测量结果表明,滚珠丝杠齿底部位的硬化层硬度及硬化层深度可以满足Φ40 mm规格滚珠丝杠的技术要求。因此,Φ40 mm规格以下的GCr15...本文采用倾斜30°感应器的表面感应加热淬火工艺处理了Φ40 mm GCr15钢滚珠丝杠。金相观察和显微硬度测量结果表明,滚珠丝杠齿底部位的硬化层硬度及硬化层深度可以满足Φ40 mm规格滚珠丝杠的技术要求。因此,Φ40 mm规格以下的GCr15钢滚珠丝杠可以采用倾斜感应器的表面感应加热淬火新工艺。展开更多
采用大功率光纤激光器同轴送粉对30Cr Ni Mo8钢转轴调质态试样表面进行激光熔覆。采用超声冲击(UIT)去应力技术对熔覆层表面进行处理,对试样的熔覆层、过渡层和母材的显微组织、硬度梯度进行了分析,采用X射线衍射法对去应力处理前后的...采用大功率光纤激光器同轴送粉对30Cr Ni Mo8钢转轴调质态试样表面进行激光熔覆。采用超声冲击(UIT)去应力技术对熔覆层表面进行处理,对试样的熔覆层、过渡层和母材的显微组织、硬度梯度进行了分析,采用X射线衍射法对去应力处理前后的残余应力分布进行了检测。结果表明,超声冲击去应力可有效改善熔覆层和过渡层的应力分布。展开更多
基金This work was supported by National Natural Science Foundation of China （51375204）, Jilin Provin- cial Science ＆ Technology Department （20140101056JC）, and Project ＂985＂ on Engineering Bionics of Jilin University. We thank Prof. Yan Shi and Dr. Jia Liu from Changchun University of Science and Technology for their help on laser heat treatment.
文摘This work investigates the potential of combining hardness gradient with surface texture （an example of bionic coupling） to improve anti-wear properties. The bionic coupling of hardness gradient and Hexagonal Texture （HT） was achieved by laser heat treatment on steel specimens with pre-engraved hexagonal surface texture. The successful establishment of decreasing hardness from surface to internal bulk was verified by hardness measurements along the depth of cross-sectioned specimens and corre- lated with the observations from metallurgical microscopy. The tribological performance of bionic coupling specimens （HT-L） was examined under dry contact condition, together with respective control specimens of individual bionic features, e.g. HT-H （of similar surface hardness generated by conventional heat treatment but without hardness gradient） and SS-L （of smooth surface treated by the same laser processing as for HT-L）. It is found that HT-L not only exhibits lower friction coefficient and less friction fluctuation than HT-H and SS-L, but also demonstrates a 〉50% reduction of wear loss compared to HT-H and SS-L （0.0343 g for HT-L vs. 0.0723 g for HT-H, P〈0.001; 0.0343 g for HT-L vs. 0.0817 g for SS-L, P〈0.001）. Corroboratively, observations with scanning electron microscopy revealed a relatively smooth surface for worn HT-L specimen, contrasting with the rugged and grooved surfaces of worn HT-H and SS-L specimens. These results indicate that the bionic coupling of hardness gradient to hexagonal texture can indeed improve anti-wear properties, affording a new strategy to wear and friction manage- ment.
文摘采用大功率光纤激光器同轴送粉对30Cr Ni Mo8钢转轴调质态试样表面进行激光熔覆。采用超声冲击(UIT)去应力技术对熔覆层表面进行处理,对试样的熔覆层、过渡层和母材的显微组织、硬度梯度进行了分析,采用X射线衍射法对去应力处理前后的残余应力分布进行了检测。结果表明,超声冲击去应力可有效改善熔覆层和过渡层的应力分布。
