Fe-28Mn-6Si-5Cr磨损性能影响因素分析

研究了添加不同含量Nb、Ti、Ce的Fe-28Mn-6Si-5Cr合金在油润滑条件下的摩擦磨损性能。结果表明,Fe-28Mn-6Si-5Cr合金的磨损质量损失明显低于45钢,且受载荷和转速的影响较小,当载荷为300 N时为最小。合金的磨损质量损失随转速的提高而增加。在相同的摩擦条件下,转速为50 r/min时,添加Nb和Ce、硬度较低的合金耐磨性最好,而转速为75 r/min时,添加0.42%Ti、硬度最高的合金表现出最佳的耐磨性。磨损表面形貌分析表明,合金的磨损表面呈平行于滑动方向的浅平润滑犁削沟,主要为切削磨损。

Shape Memory Effect of As-aged Fe-14Mn-5Si-8Cr-4Ni-0.2C Alloy

The effects of aging temperature on shape memory effect, mechanical properties and microstruc-ture of Fe-14Mn-5Si-8Cr-4Ni-0.2C shape memory alloy have been studied. The results showed that the second phase particles rich in chromium, manganese and silicon precipitate during aging, and thereby increase the hardness and strength of the alloy. The shape recovery ratio can be remarkably improved by aging and a maximum value can be obtained at 1223 K, which is 68% higher than that of the specimen in solid solution state. When the aging temperature is below 1223 K, the amount of second phase particles increases as the aging temperature increases. The size of austenite grain increases with increasing aging temperature. When the temperature is over 1223 K, the second phase particles can not precipitate. The lack of second phase particles and the increase of grain size make the hardness and shape recovery ratio drastically decrease, when the temperature is over 1223 K.

TiC沉淀析出对Fe-28Mn-6Si-5Cr合金力学行为的影响

借助微机控制电子万能试验机及硬度计对固溶态和时效态Fe-28Mn-6Si-5Cr合金力学性能进行对比实验研究,通过拉伸断口形貌的扫描电镜观察、变形组织结构的透射电镜分析、不同拉伸变形量和压痕载荷下弹性性质的表征测定,探讨了TiC沉淀析出对强度、硬度、伸长率、断面收缩率、弹性性质和形变硬化指数的影响。结果表明,Fe-28Mn-6Si-5Cr合金具有伪弹性和形变硬化"双-n"行为,其塑性变形以孪生方式为主。TiC沉淀析出抑制位错滑移,导致强度、伸长率和断面收缩率大大降低以及形变硬化指数n1和n2明显减小,但硬度略有升高,弹性性质显著改善。拉伸断裂失效机制因TiC沉淀析出由固溶态准解理断裂演变为时效态微孔聚集型断裂。