WC-Co-Ti(C,N)-Ni-Mo系硬质合金微观结构及其力学性能的影响
|
摘要
采用高真空高温(<5.5×10~(-3) Pa、1 400℃)液相烧结工艺,制备得到添加不同含量Ni元素的WC-Co-TiC-TiN-Mo系硬质合金,并且对其微观结构和力学性能进行对比研究.采用分析天平、维氏显微硬度计、X射线衍射仪(XRD)、场发射扫描电镜(SEM)等,分别分析了试样密度、显微硬度、成分以及微观结构的变化.结果表明:有Ni和无Ni两种情况下得到的试样微观结构和性能差别较大,并且硬质合金试样微观结构和力学性能随着Ni元素添加含量的变化而有所不同.当原料中不含Ni时,此种烧结工艺得到的硬质合金性能较低,表现在试样经测试得到的硬度、密度、致密性等参数均相对较低;当在WC、Co、TiC中添加Ni元素时,发现制备得到的硬质合金中,WC晶粒分布较为匀质且晶粒相对较细,试样的硬度、密度和致密性等性能也得到显著改善.进一步分析表明:当在合金粉体中添加0.75wt.%Ni时,得到的合金试样性能较佳,WC晶粒尺寸较细,试样表面维氏显微硬度为1 850HV_(10kgf),试样内部维氏显微硬度2210HV_(10kgf),相对于无添加Ni元素时合金硬度分别增加约19%和27%;同样,试样相对密度增加21%,达到99.3%,得到的合金试样更为致密、硬度更高,切削性能和刀具寿命表现更为优越.
The WC-Co-Ti(C,N)-Mo-Ni system cemented carbides containing different Ni element content were prepared by a high temperature and high vacuum liquid phase sintering technology(<5.5×10~(-3)Pa、1 400℃).The microstructure and mechanical properties were contrast to study in this paper.The density,micro-hardness,physical phases and microstructure were analyzed by analytical balance,micro-hardness tester,XRD and SEM,respectively.The influence of Ni content variation on the microstructure and mechanical properties was also analyzed.It concludes that the microstructure and mechanical properties of specimens are great influenced by the variation of Ni content.The mechanical properties such as the hardness,density and compactness of specimens are usually low while no Ni addition.However,WC grain size is small and uniform distribution when adding Ni element into raw powders.The mechanical properties of specimens are also improved while doping Ni element.It is obvious that Ni element can effectively inhibit the abnormal growth of WC grain and improve the mechanical properties of cemented carbides.Further,it founds that the inhibition effect is remarkable while the addition of Ni element content is 0.75 wt.% within the studying scope of this paper,the compactness of cemented carbides are better than the others,the highest hardness value of surface and interior in specimens is increased about 19 % and 27 %,which are improved to 1 850 HV_(10kgf)and 2 210 HV_(10kgf),respectively.The relative density value of specimens increased about 21%to 99.3%.The specimens become to more compact and harder,their cutting properties and service life are great improved,and their synthetical mechanical properties is more excellent.
The WC-Co-Ti(C,N)-Mo-Ni system cemented carbides containing different Ni element content were prepared by a high temperature and high vacuum liquid phase sintering technology(<5.5×10~(-3)Pa、1 400℃).The microstructure and mechanical properties were contrast to study in this paper.The density,micro-hardness,physical phases and microstructure were analyzed by analytical balance,micro-hardness tester,XRD and SEM,respectively.The influence of Ni content variation on the microstructure and mechanical properties was also analyzed.It concludes that the microstructure and mechanical properties of specimens are great influenced by the variation of Ni content.The mechanical properties such as the hardness,density and compactness of specimens are usually low while no Ni addition.However,WC grain size is small and uniform distribution when adding Ni element into raw powders.The mechanical properties of specimens are also improved while doping Ni element.It is obvious that Ni element can effectively inhibit the abnormal growth of WC grain and improve the mechanical properties of cemented carbides.Further,it founds that the inhibition effect is remarkable while the addition of Ni element content is 0.75 wt.% within the studying scope of this paper,the compactness of cemented carbides are better than the others,the highest hardness value of surface and interior in specimens is increased about 19 % and 27 %,which are improved to 1 850 HV_(10kgf)and 2 210 HV_(10kgf),respectively.The relative density value of specimens increased about 21%to 99.3%.The specimens become to more compact and harder,their cutting properties and service life are great improved,and their synthetical mechanical properties is more excellent.
引文
[1]FAN P,FANG Z Z,GUO J.A review of liquid phase migration and methods for fabrication of functionally graded cemented tungsten carbide[J].International Journal of Refractory Metals&Hard Materials,2013,36(1):2-9.
[2]倪海龙.奏响切削刀具行业新乐章---记2014年度中国机械工业科学技术奖一等奖项目“难加工零件高效精密切削刀具设计、制备与应用”[J].中国科技奖励,2015(3):60-60.
[3]SUN L,YANG T,JIA C,et al.VC,Cr 3C2,doped ultrafine WC-Co cemented carbides prepared by spark plasma sintering[J].International Journal of Refractory Metals&Hard Materials,2011,29(2):147-152.
[4]LIN N,WU C H,HE Y H,et al.Effect of Mo and Co additions on the microstructure and properties of WC-TiC-Ni cemented carbides[J].International Journal of Refractory Metals&Hard Materials,2012,30(1):107-113.
[5]ZHENG D,LI X,AI X,et al.Bulk WC-Al 2O3,composites prepared by spark plasma sintering[J].International Journal of Refractory Metals&Hard Materials,2012,30(1):51-56.
[6]ZHANG L,CHEN S,CHENG X,et al.Effects of cubic carbides and La additions on WC grain morphology,hardness and toughness of WC-Co alloys[J].Transactions of Nonferrous Metals Society of China,2012,22(7):1680-1685.
[7]CORREA E O,SANTOS J N,KLEIN A N.Microstructure and mechanical properties of WC-Ni-Si based cemented carbides developed by powder metallurgy[J].International Journal of Refractory Metals&Hard Materials,2010,28(5):572-575.
[8]RONG H,PENG Z,REN X,et al.Microstructure and mechanical properties of ultrafine WC-Ni-VC-TaC-cBN cemented carbides fabricated by spark plasma sintering[J].International Journal of Refractory Metals&Hard Materials,2011,29(6):733-738.
[9]MUKHOPADHYAY A,BASU B.Recent developments on WC-based bulk composites[J].Journal of Materials Science,2011,46(3):571-589.
[10]Andrén H O.Microstructures of cemented carbides[J].Materials&Design,2001,22(6):491-498.
[11]RAIHANUZZAMAN R M,XIE Z,HONG S J,et al.Powder refinement,consolidation and mechanical properties of cemented carbides-An overview[J].Powder Technology,2014,261:1-13.
[12]金狂浩.涂层和基体对PVD涂层硬质合金刀具高速车削高温合金的影响[D].中南大学,2012.
[13]晏鲜梅,熊惟皓,郑立允.金属陶瓷刀具及其表面处理的现状与展望[J].材料导报,2005,19(f05):352-355.
[14]赵立新,郑立允.TiN/TiAlN涂层Ti(C,N)基金属陶瓷刀具的切削性能[J].金属热处理,2009,34(2):18-20.
[15]KONYASHIN I,HLAWATSCHEK S,RIES B,et al.Cobalt capping on WC-Co hardmetals.Part I:A mechanism explaining the presence or absence of cobalt layers on hardmetal articles during sintering[J].International Journal of Refractory Metals&Hard Materials,2014,42(1):142-150.
[16]JANISCH D S,LENGAUER W,R9diger K,et al.Cobalt capping:Why is sintered hardmetal sometimes covered with binder?[J].International Journal of Refractory Metals&Hard Materials,2010,28(3):466-471.
[17]GARCIA J,ENGLUND S,Hagl9fF.Controlling cobalt capping in sintering process of cermets☆[J].International Journal of Refractory Metals&Hard Materials,2016,62:126-133.
[18]KONYASHIN I,HLAWATSCHEK S,RIES B,et al.Cobalt capping on WC-Co hard metals.Part II:A technology for fabrication of Co coated articles during sintering[J].International Journal of Refractory Metals&Hard Materials,2014,42(42):136-144.
[19]娄静.微波烧结YG8硬质合金的脱碳行为及其控制[D].中南大学,2011.
[20]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.
[21]SUZUKI H,HAYASHI K,TANIGUCHI Y.Theβ-Free Layer Formed near the Surface of Vacuμm-Sintered WC-β-Co Alloys Containing Nitrogen[J].Transactions of the Japan Institute of Metals,1981,22(11):758?764.
[22]张武装,刘咏,贺跃辉,等.具有梯度结构的涂层硬质合金刀片[J].中国有色金属学报,2005,15(5):757-762.
[23]TECHN D I.Diffusional control of the near-surface microstructure in functional gradient hardmetals[J].Materialwissenschaft Und Werkstofftechnik,2005,36(10):460-466.
[24]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.
[25]EKROTH M,FRYKHOLM R,LINDHOLM M,et al.Gradient zones in WC-Ti(C,N)-Cobased cemented carbides:experimental study and computer simulations[J].Acta Materialia,2000,48(9):2177-2185.
[26]GARCIA J.Influence of Fe-Ni-Co binder composition on nitridation of cemented carbides[J].International Journal of Refractory Metals&Hard Materials,2012,30(1):114-120.
[27]ZACKRISSON J,Andrén H O.Effect of carbon content on the microstructure and mechanical properties of(Ti,W,Ta,Mo)(C,N)-(Co,Ni)cermets[J].International Journal of Refractory Metals&Hard Materials,1999,17(4):265-273.
[28]CHEN X,XIONG W,QU J,et al.Microstructure and mechanical properties of(Ti,W,Ta)C-xMoNi cermets[J].International Journal of Refractory Metals&Hard Materials,2012,31(3):56-61.
[29]KOWANDA C,SPEIDEL M O.Solubility of nitrogen in liquid nickel and binary Ni-Xi,alloys(Xi=Cr,Mo,W,Mn,Fe,Co)under elevated pressure[J].Scripta Materialia,2003,48(8):1073-1078.
[30]毕泗庆.用于钢材切削加工的Fe、Ni代Co硬质合金刀具材料的研究[D].四川大学学位论文,2007.
[2]倪海龙.奏响切削刀具行业新乐章---记2014年度中国机械工业科学技术奖一等奖项目“难加工零件高效精密切削刀具设计、制备与应用”[J].中国科技奖励,2015(3):60-60.
[3]SUN L,YANG T,JIA C,et al.VC,Cr 3C2,doped ultrafine WC-Co cemented carbides prepared by spark plasma sintering[J].International Journal of Refractory Metals&Hard Materials,2011,29(2):147-152.
[4]LIN N,WU C H,HE Y H,et al.Effect of Mo and Co additions on the microstructure and properties of WC-TiC-Ni cemented carbides[J].International Journal of Refractory Metals&Hard Materials,2012,30(1):107-113.
[5]ZHENG D,LI X,AI X,et al.Bulk WC-Al 2O3,composites prepared by spark plasma sintering[J].International Journal of Refractory Metals&Hard Materials,2012,30(1):51-56.
[6]ZHANG L,CHEN S,CHENG X,et al.Effects of cubic carbides and La additions on WC grain morphology,hardness and toughness of WC-Co alloys[J].Transactions of Nonferrous Metals Society of China,2012,22(7):1680-1685.
[7]CORREA E O,SANTOS J N,KLEIN A N.Microstructure and mechanical properties of WC-Ni-Si based cemented carbides developed by powder metallurgy[J].International Journal of Refractory Metals&Hard Materials,2010,28(5):572-575.
[8]RONG H,PENG Z,REN X,et al.Microstructure and mechanical properties of ultrafine WC-Ni-VC-TaC-cBN cemented carbides fabricated by spark plasma sintering[J].International Journal of Refractory Metals&Hard Materials,2011,29(6):733-738.
[9]MUKHOPADHYAY A,BASU B.Recent developments on WC-based bulk composites[J].Journal of Materials Science,2011,46(3):571-589.
[10]Andrén H O.Microstructures of cemented carbides[J].Materials&Design,2001,22(6):491-498.
[11]RAIHANUZZAMAN R M,XIE Z,HONG S J,et al.Powder refinement,consolidation and mechanical properties of cemented carbides-An overview[J].Powder Technology,2014,261:1-13.
[12]金狂浩.涂层和基体对PVD涂层硬质合金刀具高速车削高温合金的影响[D].中南大学,2012.
[13]晏鲜梅,熊惟皓,郑立允.金属陶瓷刀具及其表面处理的现状与展望[J].材料导报,2005,19(f05):352-355.
[14]赵立新,郑立允.TiN/TiAlN涂层Ti(C,N)基金属陶瓷刀具的切削性能[J].金属热处理,2009,34(2):18-20.
[15]KONYASHIN I,HLAWATSCHEK S,RIES B,et al.Cobalt capping on WC-Co hardmetals.Part I:A mechanism explaining the presence or absence of cobalt layers on hardmetal articles during sintering[J].International Journal of Refractory Metals&Hard Materials,2014,42(1):142-150.
[16]JANISCH D S,LENGAUER W,R9diger K,et al.Cobalt capping:Why is sintered hardmetal sometimes covered with binder?[J].International Journal of Refractory Metals&Hard Materials,2010,28(3):466-471.
[17]GARCIA J,ENGLUND S,Hagl9fF.Controlling cobalt capping in sintering process of cermets☆[J].International Journal of Refractory Metals&Hard Materials,2016,62:126-133.
[18]KONYASHIN I,HLAWATSCHEK S,RIES B,et al.Cobalt capping on WC-Co hard metals.Part II:A technology for fabrication of Co coated articles during sintering[J].International Journal of Refractory Metals&Hard Materials,2014,42(42):136-144.
[19]娄静.微波烧结YG8硬质合金的脱碳行为及其控制[D].中南大学,2011.
[20]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.
[21]SUZUKI H,HAYASHI K,TANIGUCHI Y.Theβ-Free Layer Formed near the Surface of Vacuμm-Sintered WC-β-Co Alloys Containing Nitrogen[J].Transactions of the Japan Institute of Metals,1981,22(11):758?764.
[22]张武装,刘咏,贺跃辉,等.具有梯度结构的涂层硬质合金刀片[J].中国有色金属学报,2005,15(5):757-762.
[23]TECHN D I.Diffusional control of the near-surface microstructure in functional gradient hardmetals[J].Materialwissenschaft Und Werkstofftechnik,2005,36(10):460-466.
[24]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.
[25]EKROTH M,FRYKHOLM R,LINDHOLM M,et al.Gradient zones in WC-Ti(C,N)-Cobased cemented carbides:experimental study and computer simulations[J].Acta Materialia,2000,48(9):2177-2185.
[26]GARCIA J.Influence of Fe-Ni-Co binder composition on nitridation of cemented carbides[J].International Journal of Refractory Metals&Hard Materials,2012,30(1):114-120.
[27]ZACKRISSON J,Andrén H O.Effect of carbon content on the microstructure and mechanical properties of(Ti,W,Ta,Mo)(C,N)-(Co,Ni)cermets[J].International Journal of Refractory Metals&Hard Materials,1999,17(4):265-273.
[28]CHEN X,XIONG W,QU J,et al.Microstructure and mechanical properties of(Ti,W,Ta)C-xMoNi cermets[J].International Journal of Refractory Metals&Hard Materials,2012,31(3):56-61.
[29]KOWANDA C,SPEIDEL M O.Solubility of nitrogen in liquid nickel and binary Ni-Xi,alloys(Xi=Cr,Mo,W,Mn,Fe,Co)under elevated pressure[J].Scripta Materialia,2003,48(8):1073-1078.
[30]毕泗庆.用于钢材切削加工的Fe、Ni代Co硬质合金刀具材料的研究[D].四川大学学位论文,2007.