摘要
采用真空烧结法制备了板状WC晶粒WC-(Co-Ni)硬质合金,通过XRD、SEM、EDS等手段研究了Ni/(Ni+Co)比对硬质合金组织和性能的影响规律。结果表明:随着Ni/(Ni+Co)比的增大,硬质合金显微组织中板状WC晶粒的比例逐渐减少,硬质相颗粒的尺寸逐渐增大且平均长厚比逐渐减小。当Ni/(Ni+Co)比过大时,硬质合金中硬质相颗粒出现了团聚现象,使其力学性能显著降低。当Ni/(Ni+Co)比为0.3和0.5时,WC-(Co-Ni)硬质合金的综合力学性能较高,这与其硬质相颗粒较细和平均长厚比较大有关。当Ni/(Ni+Co)比为0.5时,WC-(5Co+5Ni)硬质合金具有较优的综合力学性能,其抗弯强度、硬度和断裂韧性分别为2 448 MPa、90.0HRA、21.2 MPa·m^(1/2)。
WC-(Co-Ni)cemented carbides with plate-like WC grains were produced by vacuum sintering.The effects of Ni/(Ni+Co)ratio on the microstructure and mechanical properties of WC-(Co-Ni)cemented carbides were studied by X-ray diffractometry(XRD),scanning electron microscopy(SEM)and energy dispersive spectrdmeter(EDS).The results showed that with the increasing Ni/(Ni+Co)ratio,the ratio of plate-like WC grains in the microstructure of cemented carbides decreased,the sizes of hard phase particles gradually increased,and the average length-thickness ratio of hard phase particles gradually decreased.When the Ni/(Ni+Co)ratio was too high,the hard phase particles in cemented carbides were merged together,resulting in an obvious decrease of its mechanical properties.As the Ni/(Ni+Co)ratio was 0.3 or 0.5,WC-(Co-Ni)cemented carbides exhibited good mechanical properties,which was related to the smaller hard phase particles and bigger average length-thickness ratio of hard phase particles.WC-(Co-Ni)cemented carbides with Ni/(Ni+Co)ratio of 0.5 exhibited better mechanical properties,the TRS,hardness and KIC were 2 448 MPa,90.0 HRA,21.2 MPa·m^(1/2),respectively.
出处
《材料导报》
EI
CAS
CSCD
北大核心
2017年第20期73-76,91,共5页
Materials Reports
基金
国家自然科学基金(51602145
51674118)
南京工程学院人才引进基金(YKJ201509)
江苏省先进结构材料与应用技术重点实验室开放基金(ASMA201608)
江苏高校优秀科技创新团队
关键词
板状WC晶粒
硬质合金
显微组织
力学性能
plate-like WC grains
cemented carbide
microstructure
mechanical properties
