Study On The Fabricating Technology And Properties Of C-BN Bionic Anti-wear Composite Materials

Biology body surfaces have different sized and self-assembled multilevel structure and the great mass of them belong to organic or inorganic composite materials. The organic materials have wonderful plastic and toughness properties and the inorganic materials have higher hardness. The composite materials constituted by coupling of organic and inorganic materials have high hardness and good anti-wear properties. Basing on the design theory of mechanic bionic coupling and key technology coming from the keystone item of national nature science foundation in china, the design theory of bionic coupling is bought forward. Biology body obtains the optimization of biology function and the maximization of adopting circumstance and minimization of energy consumed, which are acquired by the mutual coupling action of different morphologies and structures and materials and composing et al. In this paper, the mutual action of multi factor (components, materials, structures) is synthesized and the studies of c-BN bionic anti-wear composite materials fabricated by SPS and brazing technology were developed.C-BN super-hardness materials are polycrystalline conglomeration body fabricated using inorganic nonmetal powders under a condition and the electronic Coordination are highly stable. The key of c-BN bionic anti-wear composite materials fabricated is that liquid state solders can wet the surface of c-BN powders. Test results indicate that the wettability of Ag-based activation solders vs c-BN powders is well. The rules of effect solder compositions and brazing technological parameters (brazing temperature, holding time of brazing time and brazing vacuum degree et al) on c-BN powders performance were studied. C-BN bionic anti-wear composite materials were fabricated using brazing of smelting solders and powder solders. The tests show that the activation of Ti element in smelting solders is lower than that in powder solders after activation solders smelted. After activation solders with identical composition were smelted, the welding property of solders vs c-BN was decreased. The dependable joining among Ag-based activation solders and c-BN powders and substrate metal can be obtained using AgCuTi8Sn2 powder solders under the condition of brazing temperature 950℃and holding time 20min. The molding property of samples fabricated is well and the surface is smooth and the distribution of grains is uniform. The samples of c-BN bionic anti-wear composite materials were fixed on scratch testing machine, the phenomenon of c-BN powders fell off was not be found under 100N load. It is found that the interface reaction action mechanism among Ag and activation solders and c-BN and the changed rules of these vs c-BN wettablity.Basing on the research foundation of Ag-based activation solders brazing used to fabricate c-BN bionic anti-wear composite materials and the existent guestion, the tests were adopted to fabricate c-BN super-hardness composite materials. The price of cu-basic solders is low and the strength is high and the high-temperature is well. The wettablity angle is 85°-120°on the surface of c-BN polycrystalline plates in Cu and Cu-Ni-based alloy system, which belong to incomplete wetting. The sample surfaces take on dust-colour and the total structure of composite materials is scattered. The results of scratch testing show that the strength of c-BN bionic anti-wear composite materials fabricated is lower and the grains are easily fell off. The wettability of C-BN grains was increased by addition Ti element in Cu-based solders and the surface molding mass of those was improved by addition Sn. the regression equation between the content of alloy elements and solders peoperties was establish by the mixing tested method to optimize the the composition of Cu-based activation solders. the joining shearing strengths between Cu-based solders brazing c-BN polycrystallinte plates and 45 steel heterogeneity material arrive 210Mpa-220Mpa. The surface wetting angles arrive 25°-35°on c-BN polycrystallinte plates.Researches found the wetting mechanism of Cu-based activation solders vs c-BN grains and the interfacial micro-structures between Cu-based activation solders and c-BN grains were observed. The wetting of Cu-based activation solders vs c-BN belongs to chemical wetting and the chemical reactions happy at the interface of solders and c-BN. The results of SEM and EDS analyzed show that the mutual action is remarkable between Cu-based activation solders and c-BN grains, and there is a continuous reaction thin layer in interface, and the activation Ti element happens enrichment, and the concentration is arrived 18.70% and is higher than the content in Cu-based activation solders. The interfacial reaction produces are compound. The wetting and coalescent of Cu-based activation solders vs c-BN super-hardness materials were promoted owing to the formation of interfacial reaction compound between the grains and c-BN grains.It is investigated that the interior joint strength and the effect rule of anti-wear property of the solders and the percentage content of c-BN grains volume vs the c-BN bionic anti-wear composite materials. Increasing of percentage content of c-BN grains volume helps to increase materials anti-wear property and effect joint strength between c-BN bionic anti-wear composite materials and solders at the same time, the anti-wear property was affected at last. The investigations show that mechanics property discrepancy between solders in c-BN bionic anti-wear composite materials and c-BN grains reinforced rigid hardness phase is larger. The outside forces (pull, wallop and friction et al) can't be uniformly loaded by c-BN bionic anti-wear composite materials because the inside joint strengths in these are lower than solders strength itself and joint strength between solders and steel substrate, owing to c-BN grains reinforced rigid hardness phase fell off, and the destining efficiency of c-BN bionic anti-wear composite materials was lost. The analytic results from tests and mechanics model established show that the inside joint strength and anti-wear property in c-BN bionic anti-wear composite materials are the highest when the content of c-BN grains is from 40% to 50%. At the same testing condition, the ant-wear property of as-fabricated materials is 12.34 times of normal 45 steel quenched, the joint strengths arrive 182Mpa-187Mpa.One of the key reasons, which result in invalidation of c-BN bionic anti-wear composite materials, is c-BN groins taking off due to the less anti-wear property of based material. The structure of c-BN bionic anti-wear composite materials fabricated using brazing method is the structure of cast shape owing to the structure loosing and anti-wear property less. These materials were worn out during wearing process firstly and the comparatively protuberant high hardness c-BN grains were formed into the non-smooth surfaces to resist wearing out of abrading grains. The anti-wear property of as-fabricated materials was decreased and c-BN grains were fell off under the instance of bigger outside force. Basing on the technological characteristic of SPS, SPS technology was used to fabricate c-BN bionic anti-wear composite materials.It was researched that the influencing rule of technologic parameters vs properties of c-BN bionic anti-wear composite materials fabricated using SPS technology. The multi-factors, which include sinter technological parameters (temperature, stress, time) and materials (sizes of c-BN grains, the volume percentage content c-BN, mechanics properties of substrate alloy) and the condition of outside circumstance, have effect on properties. The research results show that sinter technological parameters is a controllable factor and effect internality mass of c-BN bionic anti-wear composite materials. Tests adopted the method of orthogonal polynomial repression design to establish regression equation of kinds of parameters and properties of c-BN bionic anti-wear composite materials. Weight between kinds of factors and properties effect was studied to optimize the model. It were ensure that technological parameters optimized of c-BN bionic anti-wear composite materials fabricated using SPS technology, axial stresses are 28Mpa-33Mpa and sintered temperatures are 780℃-800℃and holding times are 4.6min-5min.SPS technology was used to fabricate c-BN bionic anti-wear composite materials. The chemical reaction can be happened between activation element Ti in alloy and c-BN. New phases can be formed by reaction decomposing on c-BN surfaces. The key was that structure of as-fabricated materials was improved owing to grains distributed uniformly on substrate alloy and fabrication temperature lower and inside remains stress decreased and c-BN grains fragmentation avoided and joint strength increased between c-BN grains and substrate alloy. Anti-wear property of as-fabricated materials is higher than those materials fabricated using brazing method, which is 14.73 times of 45 steel quenched. As-fabricated materials have strongly adhesion effect on parts contacted under the friction heat effect and the key abrasion shape belongs to adherence abrasion with abrasive grain abrasion and fatigue abrasion.It was discussed by tests using SPS technology that integrative sintering realized among c-BN grains and Cu-based activation alloy and 45 steel. The simultaneity welding was realized between powders and steel substrate. New method was obtained to research bionic anti-wear composite materials and the other hard welding materials.