真空-压力两步烧结制备的表层脱立方相梯度硬质合金的组织与性能
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摘要
本文通过真空-压力两步烧结制备了脱立方相梯度硬质合金,并对材料的组织和性能做了研究。研究发现,相比于一步真空烧结制备的脱立方相梯度硬质合金,真空-压力两步烧结制备的梯度硬质合金脱立方相层更厚,合金内部的立方相晶粒尺寸更大。梯度硬质合金脱立方相层中的平均WC晶粒尺寸比内部的更大,这与脱立方相层中Co含量更高以及内部含Ti立方相的存在有关。梯度硬质合金中过渡层的微观硬度高于合金内部,而脱立方相层的硬度最低,微观硬度变化与Co、Ti等元素含量变化紧密相关。压力烧结对表面脱立方相层的致密化作用明显,使得脱立方相层的孔隙减少,梯度合金相对密度达到99.6%。脱立方相层厚度增加和孔隙缺陷减少促进了梯度硬质合金横向断裂强度的提高。
The gradient cemented carbides with cubic phase depleted in the surface layer were prepared by two-step vacuum and pressure sintering, and the microstructure and properties were investigated in the paper. The results show that the cubic-phase-depleted layer is thicker and the cubic phase is coarser in the inner as for the gradient cemented carbide prepared by two-step vacuum and pressure sintering than one-step vacuum sintering. The average WC grain size is larger in the cubic-phase-depleted layer than in the inner of the gradient cemented carbide, which is related with higher Co contents in the cubic-phase-depleted layer and presence of cubic phase containing Ti in the inner. The microhardness in the transition zone is higher than in the inner, while the microhardness is lowest in the cubic-phase-depleted layer. The variation of microhardness is strongly correlated with the Co and Ti contents. The pressure sintering promotes the densification significantly in the cubic-phase-depleted layer, reducing the porosity and causing the relative density to reach 99.6%. The increase of cubic-phase-depleted layer thickness and decrease of pore defects improve the transverse rupture strength of the gradient cemented carbide.
The gradient cemented carbides with cubic phase depleted in the surface layer were prepared by two-step vacuum and pressure sintering, and the microstructure and properties were investigated in the paper. The results show that the cubic-phase-depleted layer is thicker and the cubic phase is coarser in the inner as for the gradient cemented carbide prepared by two-step vacuum and pressure sintering than one-step vacuum sintering. The average WC grain size is larger in the cubic-phase-depleted layer than in the inner of the gradient cemented carbide, which is related with higher Co contents in the cubic-phase-depleted layer and presence of cubic phase containing Ti in the inner. The microhardness in the transition zone is higher than in the inner, while the microhardness is lowest in the cubic-phase-depleted layer. The variation of microhardness is strongly correlated with the Co and Ti contents. The pressure sintering promotes the densification significantly in the cubic-phase-depleted layer, reducing the porosity and causing the relative density to reach 99.6%. The increase of cubic-phase-depleted layer thickness and decrease of pore defects improve the transverse rupture strength of the gradient cemented carbide.
引文
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[3]Zhang W,Du Y,Chen W,et al.CSUDDCC1-A diffusion database for multicomponent cemented carbides[J].International Journal of Refractory Metals&Hard Materials,2014,43(3):164-180.
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[6]Yang Tian'en,Sun Lan,Xiong Ji,et al.Adherent coating on gradient cemented carbide with ultrafine Ti(C0.5,N0.5)[J].Rare Metals,2015,34(6):413-420.
[7]Suzuki H,Hayashi K,Taniguchi Y.Theβ-free layer formed near the surface of vacuum-sintered WC-β-Co alloys containing nitrogen[J].Transactions of the Japan Institute of Metals,1981,22(11):758-764.
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[12]Garcia J.Investigations on kinetics of formation of fcc-free surface layers on cemented carbides with Fe-Ni-Co binders[J].International Journal of Refractory Metals&Hard Materials,2011,29(2):306-311.
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[14]Zhang W,Du Y,Peng Y.Effect of Ta C and Nb C addition on the microstructure and hardness in graded cemented carbides:simulations and experiments[J].Ceramics International,2015,42(1):428-435.
[15]Zhang W,Du Y,Peng Y,et al.Experimental investigation and simulation of the effect of Ti and N contents on the formation of fccfree surface layers in WC-Ti(C,N)-Co cemented carbides[J].International Journal of Refractory Metals&Hard Materials,2013,41(11):638-647.
[16]Zhou X,Wang K,Xu Z,et al.Effect of powder particle size on gradient formation and grain growth in ultrafine crystalline gradient cemented carbide[J].International Journal of Refractory Metals&Hard Materials,2016,56:63-68.
[17]Xiong J,Guo Z,Yang M,et al.Effect of ultra-fine Ti C0.5N0.5 on the microstructure and properties of gradient cemented carbide[J].Journal of Materials Processing Technology,2009,209(12-13):5293-5299.
[18]Yang Tian'en,Sun Lan,Xiong Ji,et al.Microstructure and properties of gradient cemented carbide with nano-Ti N[J].Wuhan Univ Technol(Mater Sci Ed),2014,29(1):102-108.
[19]Tang J,Xiong J,Guo Z,et al.Microstructure and properties of CVD coated on gradient cemented carbide with different WC grain size[J].International Journal of Refractory Metals&Hard Materials,2016,61:128-135.
[20]Frykholm R,Jansson B,Andrén H O.Methods for atom probe analysis of microgradients in functionally graded cemented carbides[J].Micron,2002,33(7-8):639-646.
[21]Ekroth M,Frykholm R,Lindholm M,et al.Gradient zones in WCTi(C,N)-Co-based cemented carbides:experimental study and computer simulations[J].Acta Materialia,2000,48(9):2177-2185.
[22]Techn D I.Diffusional control of the near-surface microstructure in functional gradient hardmetals[J].Materialwissenschaft Und Werkstofftechnik,2005,36(10):460-466.
[23]张武装,刘咏,贺跃辉,等.一种特殊烧结技术对梯度结构硬质合金性能影响的研究[J].功能材料,2007,38(2):292-294.Zhang Wuzhuang,Liuyong,He Yuehui,et al.Study on the coated cemented carbide with gradient structure by a special sintering technology[J].Functional materials,2007,38(2):292-294.
[24]张武装,刘咏,王海兵,等.烧结方式对硬质合金梯度结构和性能的影响[J].硬质合金,2004,21(4):193-196.Zhang Wuzhuang,Liuyong,Wang Haibing,et al.The effect of sintering methods on the structure and properties of graded cemented carbides[J].Cemented carbide,2004,21(4):193-196.
[25]蔡俊,丰平,贺跃辉.烧结工艺对梯度结构硬质合金梯度层组织和厚度的影响[J].硬质合金,2007,24(2):91-95.Cai Jun,Feng Ping,He Yuehui.The effect of sintering process on microstructure and thickness of graded layer of functionally graded cemented carbides[J].Cemented carbide,2007,24(2):91-95.
[26]Zhou X,Xu Z,Wang K,et al.One-step Sinter-HIP method for preparation of functionally graded cemented carbide with ultrafine grains[J].Ceramics International,2016,42(4):5362-5367.
[27]Yang Tian'en,Xiong Ji.Microstructure,composition distribution and rupture performance of WC-(Ti,W)C-Ti(C,N)-Co gradient cemented carbonitrides with varied nitrogen[J].Mater Res.,2016,31(23):3795-3804.
[28]Xu S,Yang T,Xiong J,et al.Carbon contents design and characterization of gradient cemented carbonitrides with nano-Ti N addition[J].Ceramics International,2017,43(6):5127-5135.
[29]曾青,吴恩熙.低压烧结对硬质合金机械性能的影响[J].硬质合金,1995,2:82-84.Zeng Qing,Wu Enxi.The effect of sintering/HIP on mechanical property of cemented carbide[J].Cemented Carbide,1995,2:82-84.
[30]陈利,吴恩熙,王社权,等.WC-Ti(C,N)-Co梯度硬质合金表面韧性区的形成机理[J].中南大学学报(自然科学版),2006,37(4):650-654.Chen Li Wu Enxi,Wang Shequan,et al.Formation mechanism of surface ductile zones in WC-Ti(C,N)-Co gradient cemented carbide[J].J Cent South Univ(Science and technology),2006,37(4):650-654.
[31]吴恩熙,陈利,张静,等.真空/压力烧结对硬质合金脱β层的影响[J].硬质合金,2005,22(1):20-22.Wu Enxi,Chen Li,Zhang Jing,et al.The effect of vacuum/pressure sintering on the rich cobalt layer of cemented carbide[J].Cemented Carbide,2005,22(1):20-22.
[32]Schubert WD,Neumeister H,Kinger G,Lux B.Hardness to toughness relationship of fine-grained WC-Co hardmetals[J].International Journal of Refractory Metals and Hard Materials,1998,16:133-142.
[33]Chen L,Lengauer W,Ettmayer P,et al.Fundamentals of liquid phase sintering for modern cermets and functionally graded cemented carbonitrides(FGCC)[J].International Journal of Refractory Metals&Hard Materials,2000,18(6):307-322.
[34]G arcia J,Prat O.Experimental investigations and DICTRA simulations on formation of diffusion-controlled fcc-rich surface layers on cemented carbides[J].Applied Surface Science,2011,257(21):8894-8900.
[35]Streitenberger P,Z?llner D.The envelope of size distributions in Ostwald ripening and grain growth[J].Acta Materialia,2015,88:334-345.
[36]Li J,Guo C,Ma Y,et al.Effect of initial particle size distribution on the dynamics of transient Ostwald ripening:A phase field study[J].Acta Materialia,2015,90:10-26.
[37]Morton C W,Wills D J,Stjernberg K.The temperature ranges for maximum effectiveness of grain growth inhibitors in WC-Co alloys[J].International Journal of Refractory Metals&Hard Materials,2005,23(4-6):287-293.
[38]Loucif A,Figueiredo R B,Baudin T,et al.Ultrafine grains and the Hall-Petch relationship in an Al-Mg-Si alloy processed by high-pressure torsion[J].Materials Science&Engineering A,2012,532(1):139-145.
[39]Guo Z,Xiong J,Yang M,et al.WC-Ti C-Ni cemented carbide with enhanced properties[J].Journal of Alloys&Compounds,2008,465(1):157-162.
[40]Love A,Luyckx S,Sacks N.Quantitative relationships between magnetic properties,microstructure and composition of WC-Co alloys[J].Alloy.Compd.2010,489:465-468.
[41]Cho,K.H.,Chung,I.S.Lee.The influence of carbon content of the properties of binder and carbide phase of cemented carbide[J].Interceram,1999,48:30-34.
[42]Wu C H,Zhang T Q.Formation mechanisms of microstructure imperfections and their effects on strength in submicron cemented carbide[J].International Journal of Refractory Metals&Hard Materials,2013,40(9):8-13.
[43]Suzuki H,Hayashi K.Relations between transverse-rupture strength and fracture origin in WC-10%Co cemented carbides[J].Journal of the Japan Institute of Metals,1974,38(11):1013-1019.
[44]Frykholm R,Andrén H O.Development of the microstructure during gradient sintering of a cemented carbide[J].Materials Chemistry&Physics,2001,67(1):203-208.
[45]Zhang W,Peng Y,Zhou P,et al.Experimental investigation and computer simulation of gradient zone formation in WC-Ti(C,N)-Ta CNb C-Co cemented carbides[J].Journal of Phase Equilibria and Diffusion,2013,34(3):202-210.
[2]Fitzsimmons M,Sarin V K.Development of CVD WC-Co coatings[J].Surface&Coatings Technology,2001,137(2-3):158-163.
[3]Zhang W,Du Y,Chen W,et al.CSUDDCC1-A diffusion database for multicomponent cemented carbides[J].International Journal of Refractory Metals&Hard Materials,2014,43(3):164-180.
[4]Liu Y,Wang H B,Long Z Y,et al.Enhancement on the transverse fracture strength of functional graded structure cemented carbides[J].J Mater Sci.,2005,40:5525-5527.
[5]Chen L,Wu E X,Yin F,et al.Effects of gradient structure on the microstructures and properties of coated cemented carbides[J].J.Univ.Sci.Technol.Beijing,2006,13(4):363-367.
[6]Yang Tian'en,Sun Lan,Xiong Ji,et al.Adherent coating on gradient cemented carbide with ultrafine Ti(C0.5,N0.5)[J].Rare Metals,2015,34(6):413-420.
[7]Suzuki H,Hayashi K,Taniguchi Y.Theβ-free layer formed near the surface of vacuum-sintered WC-β-Co alloys containing nitrogen[J].Transactions of the Japan Institute of Metals,1981,22(11):758-764.
[8]Schwarzkopf M,Exner H E,Fischmeister H F,et al.Kinetics of compositional modification of(W,Ti)C-WC-Co alloy surfaces[J].Materials Science&Engineering A,1988,105(88):225-231.
[9]Frykholm R,Ekroth M,Jansson B,et al.Effect of cubic phase composition on gradient zone formation in cemented carbides[J].International Journal of Refractory Metals&Hard Materials,2001,19(4):527-538.
[10]Frykholm R,Jansson B,Andrén H O.The influence of carbon content on formation of carbo-nitride free surface layers in cemented carbides[J].International Journal of Refractory Metals&Hard Materials,2002,20(20):345-353.
[11]Mohammadpour M,Abachi P,Pourazarang K.Effect of cobalt replacement by nickel on functionally graded cemented carbonitrides[J].International Journal of Refractory Metals&Hard Materials,2012,30(1):42-47.
[12]Garcia J.Investigations on kinetics of formation of fcc-free surface layers on cemented carbides with Fe-Ni-Co binders[J].International Journal of Refractory Metals&Hard Materials,2011,29(2):306-311.
[13]Garcia J,Lindwall G,Prat O,et al.Kinetics of formation of graded layers on cemented carbides:Experimental investigations and DICTRA simulations[J].International Journal of Refractory Metals&Hard Materials,2011,29(2):256-259.
[14]Zhang W,Du Y,Peng Y.Effect of Ta C and Nb C addition on the microstructure and hardness in graded cemented carbides:simulations and experiments[J].Ceramics International,2015,42(1):428-435.
[15]Zhang W,Du Y,Peng Y,et al.Experimental investigation and simulation of the effect of Ti and N contents on the formation of fccfree surface layers in WC-Ti(C,N)-Co cemented carbides[J].International Journal of Refractory Metals&Hard Materials,2013,41(11):638-647.
[16]Zhou X,Wang K,Xu Z,et al.Effect of powder particle size on gradient formation and grain growth in ultrafine crystalline gradient cemented carbide[J].International Journal of Refractory Metals&Hard Materials,2016,56:63-68.
[17]Xiong J,Guo Z,Yang M,et al.Effect of ultra-fine Ti C0.5N0.5 on the microstructure and properties of gradient cemented carbide[J].Journal of Materials Processing Technology,2009,209(12-13):5293-5299.
[18]Yang Tian'en,Sun Lan,Xiong Ji,et al.Microstructure and properties of gradient cemented carbide with nano-Ti N[J].Wuhan Univ Technol(Mater Sci Ed),2014,29(1):102-108.
[19]Tang J,Xiong J,Guo Z,et al.Microstructure and properties of CVD coated on gradient cemented carbide with different WC grain size[J].International Journal of Refractory Metals&Hard Materials,2016,61:128-135.
[20]Frykholm R,Jansson B,Andrén H O.Methods for atom probe analysis of microgradients in functionally graded cemented carbides[J].Micron,2002,33(7-8):639-646.
[21]Ekroth M,Frykholm R,Lindholm M,et al.Gradient zones in WCTi(C,N)-Co-based cemented carbides:experimental study and computer simulations[J].Acta Materialia,2000,48(9):2177-2185.
[22]Techn D I.Diffusional control of the near-surface microstructure in functional gradient hardmetals[J].Materialwissenschaft Und Werkstofftechnik,2005,36(10):460-466.
[23]张武装,刘咏,贺跃辉,等.一种特殊烧结技术对梯度结构硬质合金性能影响的研究[J].功能材料,2007,38(2):292-294.Zhang Wuzhuang,Liuyong,He Yuehui,et al.Study on the coated cemented carbide with gradient structure by a special sintering technology[J].Functional materials,2007,38(2):292-294.
[24]张武装,刘咏,王海兵,等.烧结方式对硬质合金梯度结构和性能的影响[J].硬质合金,2004,21(4):193-196.Zhang Wuzhuang,Liuyong,Wang Haibing,et al.The effect of sintering methods on the structure and properties of graded cemented carbides[J].Cemented carbide,2004,21(4):193-196.
[25]蔡俊,丰平,贺跃辉.烧结工艺对梯度结构硬质合金梯度层组织和厚度的影响[J].硬质合金,2007,24(2):91-95.Cai Jun,Feng Ping,He Yuehui.The effect of sintering process on microstructure and thickness of graded layer of functionally graded cemented carbides[J].Cemented carbide,2007,24(2):91-95.
[26]Zhou X,Xu Z,Wang K,et al.One-step Sinter-HIP method for preparation of functionally graded cemented carbide with ultrafine grains[J].Ceramics International,2016,42(4):5362-5367.
[27]Yang Tian'en,Xiong Ji.Microstructure,composition distribution and rupture performance of WC-(Ti,W)C-Ti(C,N)-Co gradient cemented carbonitrides with varied nitrogen[J].Mater Res.,2016,31(23):3795-3804.
[28]Xu S,Yang T,Xiong J,et al.Carbon contents design and characterization of gradient cemented carbonitrides with nano-Ti N addition[J].Ceramics International,2017,43(6):5127-5135.
[29]曾青,吴恩熙.低压烧结对硬质合金机械性能的影响[J].硬质合金,1995,2:82-84.Zeng Qing,Wu Enxi.The effect of sintering/HIP on mechanical property of cemented carbide[J].Cemented Carbide,1995,2:82-84.
[30]陈利,吴恩熙,王社权,等.WC-Ti(C,N)-Co梯度硬质合金表面韧性区的形成机理[J].中南大学学报(自然科学版),2006,37(4):650-654.Chen Li Wu Enxi,Wang Shequan,et al.Formation mechanism of surface ductile zones in WC-Ti(C,N)-Co gradient cemented carbide[J].J Cent South Univ(Science and technology),2006,37(4):650-654.
[31]吴恩熙,陈利,张静,等.真空/压力烧结对硬质合金脱β层的影响[J].硬质合金,2005,22(1):20-22.Wu Enxi,Chen Li,Zhang Jing,et al.The effect of vacuum/pressure sintering on the rich cobalt layer of cemented carbide[J].Cemented Carbide,2005,22(1):20-22.
[32]Schubert WD,Neumeister H,Kinger G,Lux B.Hardness to toughness relationship of fine-grained WC-Co hardmetals[J].International Journal of Refractory Metals and Hard Materials,1998,16:133-142.
[33]Chen L,Lengauer W,Ettmayer P,et al.Fundamentals of liquid phase sintering for modern cermets and functionally graded cemented carbonitrides(FGCC)[J].International Journal of Refractory Metals&Hard Materials,2000,18(6):307-322.
[34]G arcia J,Prat O.Experimental investigations and DICTRA simulations on formation of diffusion-controlled fcc-rich surface layers on cemented carbides[J].Applied Surface Science,2011,257(21):8894-8900.
[35]Streitenberger P,Z?llner D.The envelope of size distributions in Ostwald ripening and grain growth[J].Acta Materialia,2015,88:334-345.
[36]Li J,Guo C,Ma Y,et al.Effect of initial particle size distribution on the dynamics of transient Ostwald ripening:A phase field study[J].Acta Materialia,2015,90:10-26.
[37]Morton C W,Wills D J,Stjernberg K.The temperature ranges for maximum effectiveness of grain growth inhibitors in WC-Co alloys[J].International Journal of Refractory Metals&Hard Materials,2005,23(4-6):287-293.
[38]Loucif A,Figueiredo R B,Baudin T,et al.Ultrafine grains and the Hall-Petch relationship in an Al-Mg-Si alloy processed by high-pressure torsion[J].Materials Science&Engineering A,2012,532(1):139-145.
[39]Guo Z,Xiong J,Yang M,et al.WC-Ti C-Ni cemented carbide with enhanced properties[J].Journal of Alloys&Compounds,2008,465(1):157-162.
[40]Love A,Luyckx S,Sacks N.Quantitative relationships between magnetic properties,microstructure and composition of WC-Co alloys[J].Alloy.Compd.2010,489:465-468.
[41]Cho,K.H.,Chung,I.S.Lee.The influence of carbon content of the properties of binder and carbide phase of cemented carbide[J].Interceram,1999,48:30-34.
[42]Wu C H,Zhang T Q.Formation mechanisms of microstructure imperfections and their effects on strength in submicron cemented carbide[J].International Journal of Refractory Metals&Hard Materials,2013,40(9):8-13.
[43]Suzuki H,Hayashi K.Relations between transverse-rupture strength and fracture origin in WC-10%Co cemented carbides[J].Journal of the Japan Institute of Metals,1974,38(11):1013-1019.
[44]Frykholm R,Andrén H O.Development of the microstructure during gradient sintering of a cemented carbide[J].Materials Chemistry&Physics,2001,67(1):203-208.
[45]Zhang W,Peng Y,Zhou P,et al.Experimental investigation and computer simulation of gradient zone formation in WC-Ti(C,N)-Ta CNb C-Co cemented carbides[J].Journal of Phase Equilibria and Diffusion,2013,34(3):202-210.