Study On Tribological Properties And Fabrication Of WC-TiC-Ni Layer Ceramic Cutting Tool Toughened By Carbon Fiber Braid

High-speed cutting technology with high machining efficiency and machining precision plays an important role in the field of machining;High-speed cutting technology has higher requirements for cutting tools’ performance.At present,the common tools used in the field of high speed cutting are: Hard alloy cutting tools,metal ceramic cutting tools,diamond tools,ceramic cutting tools etc.Among them,the ceramic cutting tools have been widely concerned due to its superior performance and low price.However,the disadvantage of the low toughness of ceramic cutting tools seriously restricted its further promotion and application.Aiming at the disadvantages of the ceramic cutting tools,the WC-TiC-Ni layer ceramic cutting tool toughened by carbon fiber braid have been designed and fabricated.In this paper,the effects of TiC content 、 sintering temperature and holding time on the mechanical properties and microstructure of the WC-TiC-Ni layer ceramic cutting tool toughened by carbon fiber braid were studied;The strengthening and toughening mechanism of the cutting tool were analyzed;The friction and wear properties between ceramic cutting tools and difficult-to-machine materials were studied.Firstly,in this paper,the design principle of WC-TiC-Ni layer ceramic cutting tool toughened by carbon fiber braid was proposed.And according to the design principle,the nano WC and TiC were chosen as the matrix phase and additive phases respectively;Ni was chosen as the binder phase and its wettability was analyzed;The chemical compatibility and physical compatibility of materials were analyzed,and it was proved that the materials chosen in this paper were in accordance with the design principle of layer ceramic cutting tool.Secondly the effects of TiC content,sintering temperature and holding time on the mechanical properties and microstructure of WC-TiC-Ni layer ceramic cutting tool toughened by carbon fiber braid were studied.When the sintering temperature is 1500℃,the sintering pressure is 20 MPa and the content of TiC is 10 wt.%,the bending strength of the CWT11 ceramic cutting tool with holding time of 30 min was the highest,reaching 905.30 MPa,the Vickers hardness and fracture toughness of the CWT31 ceramic cutting tool with holding time of 45 min reached the maximum of 20.21 GPa and 12.55MPa·m1/2 respectively.The effects of sintering temperature,Ti C content and holding time on the microstructure of WC-TiC-Ni layer ceramic cutting tool toughened by carbon fiber braid were analyzed.And the strengthening and toughening mechanism of the cutting tools were studied.The research results show that the grain size and porosity increased with the increase of TiC content,sintering temperature and holding time,which is the main reason that affects the performance of the material.The main toughening methods of ceramic cutting tool materials are crack deflection toughening,crack bridging toughening,crack bifurcation toughening,fiber toughening,layered composite toughening and so on.There are two kinds of fracture modes: intergranular fracture and transgranular fracture.Finally,the dry tribological properties between the tool samples and 316 L austenitic stainless steel,GCr15 bearing steel and TC4 titanium alloy was studied.Through the test of the friction factor and wear rate between the materials under different sliding speeds and loads,the effects of sintering temperature,TiC content and holding time on the friction factor and wear rate of the tool samples were revealed.In addition,the influence of sliding speed and load on the friction factor and wear rate of the material were also obtained.