珠光体型FeCoNiTi高熵合金的微结构与耐磨性能

Microstructure and wear resistance of pearlitic FeCoNiTi high-entropy alloys

以Fe_(49)Co_(25)Ni_(20)Ti_(6)中熵合金为研究对象,通过共析转变,获得层片状共析组织,采用扫描电子显微镜、透射电子显微镜及摩擦磨损试验研究了珠光体组织的形成、特征及耐磨性能。结果表明,中熵合金在550℃发生共析转变,形成由体心立方(BCC)和Ni_(3)Ti构成的层片状共析组织,层片间距在80~100 nm;冷轧形变量与珠光体组织的形成呈正相关,经过85%轧制后,样品很短时间内达到峰时效,而且可以显著提升合金的维氏硬度,峰时效维氏硬度(HV)为(813±24)。摩擦磨损试验结果表明,85-CR和85-CR-550样品的磨损率分别为1.07×10^(-4)mm^(3)/(N·m)和2.4×10^(-5)mm^(3)/(N·m),85-CR-550样品的耐磨性能要高于85-CR,这主要得益于珠光体组织的产生。

A high-entropy alloy with the composition of Fe_(49)Co_(25)Ni_(20)Ti_(6)is studied in this contribution,and lamellar pearlitic structure has been obtained in this alloy through eutectoid transformation.The formation,characteristics and wear resistance of the pearlite have been studied by SEM,TEM and wear tests.The results show that the high-entropy alloy undergoes eutectoid transformation at 550℃,forming lamellar pearlite composed of BCC and Ni_(3)Ti,with the interlamellar spacing between 80—100 nm.The amount of cold rolling deformation is positively correlated with the formation of pearlite structure.The samples after 85%cold rolling reach the peak aging in a very short time,and the hardness of the alloy can be significantly improved with the peak aging Vickers hardness of(813±24).The wear test results show that the wear rates of the 85-CR and 85-CR-550 samples are 1.07×10^(-4)mm^(3)/(N·m)and 2.4×10^(-5)mm^(3)/(N·m),respectively.The wear resistance of 85-CR-550 sample is better than that of 85-CR,which is mainly due to the formation of pearlite structure.