Chen Zhiguo, Miao Sen, Kong Lingnan, Wei Xiang, Zhang Feihong, Yu Hongbin
School of Materials Science and Engineering, Central South University, Changsha 410083, China.
Department of Mechanical and Electrical Engineering, Hunan University of Humanities, Science and Technology, Loudi 417000, China.
Materials (Basel). 2020 Feb 21;13(4):975. doi: 10.3390/ma13040975.
The microstructure evolution, mechanical properties, and tribological properties of high boron cast steel (HBCS) with various Mo concentrations are investigated. The results indicate that Mo addition can significantly modify the microstructure and enhance the comprehensive properties. With the increase of Mo concentration, borides change from the original fish-bone Fe-rich and Cr-rich MB to dendritic Fe-rich MB, blocky and cluster-like Cr-rich MB, and grainy Mo-rich MB. The hardness of HBCS increases gradually with the increase of Mo content due to the solid solution strengthening and the refinement of MB. It can be found that all the samples exhibit quasi-cleavage, but the impact toughness increases firstly and reaches the maximum value when the concentration of Mo is 2.10 wt.%, which is the result of the dispersive distribution of MB rather than the original fish-bone MB. Subsequently, the impact toughness begins to decrease as the concentration of Mo further increases because of the extensive formation of grainy Mo-rich MB at the grain boundary. Meanwhile, the wear results reveal that the average friction coefficient and wear ratio decrease with the increase of Mo content, and the wear mechanism changes from abrasive wear and adhesive wear to abrasive wear when the concentration of Mo exceeds 2.10 wt.%.
研究了不同钼含量的高硼铸钢（HBCS）的微观结构演变、力学性能和摩擦学性能。结果表明，添加钼可显著改变微观结构并提高综合性能。随着钼含量的增加，硼化物从原来的鱼骨状富铁和富铬MB转变为树枝状富铁MB、块状和簇状富铬MB以及颗粒状富钼MB。由于固溶强化和MB的细化，HBCS的硬度随着钼含量的增加而逐渐增加。可以发现，所有样品均呈现准解理，但冲击韧性先增加，当钼浓度为2.10 wt.%时达到最大值，这是MB分散分布而非原来鱼骨状MB的结果。随后，随着钼浓度进一步增加，冲击韧性开始下降，这是由于在晶界处广泛形成颗粒状富钼MB所致。同时，磨损结果表明，平均摩擦系数和磨损率随钼含量的增加而降低，当钼浓度超过2.10 wt.%时，磨损机制从磨粒磨损和粘着磨损转变为磨粒磨损。
