SiC添加量对WC-Co硬质合金微观结构和性能的影响

Effect of SiC Addition on Microstructure and Properties of WC-Co Cemented Carbides

SiC作为陶瓷复合材料增韧相能够大大提高陶瓷复合材料的机械性能,使得SiC在陶瓷刀具的应用得到了充分的研究与长足的发展。为了研究纳米SiC添加量对WC-Co合金微观结构、力学性能和切削加工性能的影响,本研究根据控制变量法,设置SiC添加量为0%、0.5%、1.0%、1.5%和2%(质量分数,下同)5个试验组,通过粉末烧结将其烧结成块并进行SEM测试以及机械性能测试,再将5个试验组的粉末制成同一型号的刀具进行切削试验。结果表明,SiC对合金中WC硬质相晶粒生长具有一定的抑制效果,但过量的SiC易导致硬质合金中Co池的出现。当SiC添加量为1.0%时,硬质合金的硬度和断裂韧性均达到最高值,分别为92.1HRA、1576HV30和10.2MPa·m^(1/2)。使用含SiC硬质合金刀具对GH4169高温合金进行切削试验,结果表明,当SiC添加量为1.0%时,后刀面磨损量最小,约为0.16mm,当SiC添加量为2.0%时,后刀面磨损加大,为0.37mm。

As a toughening phase of ceramic composites,SiC can greatly improve the mechanical properties of ceramic composites.Therefore,the application of SiC in ceramic tools has been fully developed.For the purpose of studying the effect of nano-SiC powder addition on the microstructure,mechanical properties and machinability of WC-Co alloy,five experimental groups with SiC powder addition of 0%,0.5%,1.0%,1.5%and 2.0%(mass fraction)were set up according to the control variable method.The powder was sintered into blocks for SEM test and mechanical properties test.The powders of five experimental groups were made into the same type of tools for cutting test.The results show that:the SiC additive can inhibit the grain growth of WC hard phase in the alloy to some extent,but excessive SiC can easily lead to the appearance of Co pool in the alloy.When the content of SiC is 1.0%,the hardness and fracture toughness of cemented carbide reach the highest values,which are 92.1 HRA,1576 HV30 and 10.2 MPa·m^(1/2)respectively.The cutting test of GH4169 superalloy shows that when the content of SiC is 1.0%,the flank wear is the smallest,about 0.16 mm,and when the content of SiC is 2.0%,the flank wear increases,about 0.37 mm.