采用第一原理赝势平面波方法和基于虚拟晶体势函数近似(VCA),计算了Ag合金化(浓度x1.0%,原子分数,下同)时完整与缺陷B2-NiAl晶体的弹性性质,并采用弹性常数C44,Cauchy压力参数(C12-C44)、弹性模量E、剪切模量G及其与体模量B0的比值G/B0等,表征和评判了Ag合金化浓度x对NiAl金属间化合物延性与硬度的影响。结果表明:无论是无缺陷的理想NiAl晶体,还是含Ni空位或Ni反位的NiAl缺陷晶体,x1%的Ag合金化均可使其硬度大幅提高;在0%～0.6%以及0.7%～1%区间,Ag将提高NiAl完整晶体材料的延性,并且以0.6%附近为最好;当x≤0.5%时,Ag合金化能改善Ni空位的NiAl多晶材料延性,并以x=0.32%～0.48%时,Ni空位的NiAl多晶延性的提升幅度尤为明显;而当1%x0.5%时,却可明显提高Ni反位B2-NiAl晶体的延展性,并在x=0.73%～1%区间呈现相对较好的韧化效果。上述结论归于低浓度Ag的固溶强化与高浓度Ag的富Ag相软化作用。
Abstract
Using the first-principles pseudopotential plane-wave methods based on the density functional theory,the elastic constants of B2-(Ni1-xAgx)Al(x=0~1%,atom fraction,) supercells with or without Ni vacancy or Ni anti-site defect were calculated in the framework of Virtual Crystal Approximation.Several parameters such as elastic constant C44,Cauchy pressure(C12-C44),Elastic modulus E,the shear modulus G and their ratio G/B0 were adopted to characterize and assess the effect of Ag alloying concentration on the ductility and hardness of NiAl intermetallic compounds.Ag addition with x1% is proved to be efficient to enforce the strength or hardness of NiAl intermetallic compounds either for perfect crystals or for defect crystals.Adding Ag in the range of 0 to 0.6% and 0.7% to 1%,especially about 0.6%,help to improve the ductility of perfect B2-NiAl.Ni vacancy or Ni anti-site defects make the intrinsic ductility of perfect B2-NiAl crystals without Ag addition to be weakened.Moreover,the ductility of B2-(Ni1-xAgx) Al crystals with Ni vacancies or Ni anti-site is obviously improved as Ag alloying concentration x is lower than 0.5%(0.32% to 0.48%,especially) or is in the range of 0.5% to 1%(0.73% to 1%,especially) respectively.The alloying effect attribute to solid solution hardening of Ag atom in low concentration and inteneration of Ag-rich phase in high concentration.
关键词
B2-NiAl /
Ag合金化 /
第一原理计算 /
弹性性质
{{custom_keyword}} /
Key words
B2-NiAl /
Ag alloying /
pseudopotential plan /
elastic properties
{{custom_keyword}} /
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
DAROLIA R.Structural applications of NiAl[J].J Mater Sci Technol,1994,10(3):157-169.
MORINAGA M,SAITO J,YUKAWA N,et al.Electronic effect on the ductility of alloyed TiAl compound[J].Acta Mater,1990,38(1):25-29.
刘震云,林栋梁,黄伯云,等.NiAl金属间化合物研究现状[J].机械工程材料,1998,22(2):1-5.
周健,郭建亭,李谷松.Ag对NiAl合金组织和性能的影响[J],材料工程,2002,3:7-10.
DAROLIA R,LAHRMAN D,FIELD R.The effect of iron,gallium and molybdenum on the room temperature tensile ductility of NiAl[J].Scripta Metall Mater,1992,26(7):1007-1012.
MUNROE P R,GEORGE M,BAKER I,et al.Microstructure,mechanical properties and wear of Ni-Al-Fe alloys[J].Mater Sci Eng A,2002,325(1):1-8.
陈律,彭平,李贵发,等.L10-TiAl金属间化合物Mn、Nb合金化电子结构的计算[J].航空材料学报,2005,25(5):15-19.
陈律,彭平,韩绍昌.B2-YX(X=Cu,Rh,Ag,In)点缺陷结构及其基本物性的理论计算[J].稀有金属材料与工程.2007,36(12):2089-2093.
陈律,彭平,李贵发,等.B2-RuAl点缺陷结构的第一原理计算[J].稀有金属材料与工程.2006,35(7):1065-1070.
陈律,彭平,韩亚利.L10-TiAl基本物性的计算与比较研究[J].材料科学与工艺,2007(1):47-51.
陈律,彭平,湛建平,等.Ru合金化Ni/Ni3Al相界断裂功的第一原理计算[J].中国有色金属学报,2008,18(5):890-896.
XU D S,LI D,HU Z Q.Substitution Behavior in NiAl-a First Principle Prediction Considering Lattice Relaxation[J].Mater Res Soc Symp Proc,1999,538:377-382.
郭建亭.有序金属间化合物镍铝合金[M],北京:科学出版社,2003:66-69.
SEGALL M D,LINDAN PHILIP J D,PROBERT M J,et al.First-principles simulation:ideas,illustrations and the CASTEP code[J].J Phys:Condens Matter,2002,14(11):2717-2744.
VANDERBILT D.Soft self-consistent pseudopotentials in a generalized eigenvalue formalism[J].Phys Rev B,1990,41 (11):7892-7895.
MARLO M,MILMAN V.Density-functional study of bulk and surface properties of titanium nitride using different exchange-correlation functionals[J].Phys Rev B,2000,62(4):2899-2907.
WHITE J A,BIRD D M.Implementation of gradient-corrected exchange-correlation potentials in car-parrinello total-energy calculations[J].Phys Rev B,1994,50(7):4954-4957.
FISCHER T H,ALMLOF J.General methods for geometry and wave function optimization[J].J Phys Chem,1992,96 (24):9768-9774.
FRANCIS G P,PAYNE M C.Finite basis set corrections to total energy pseudopotential calculations[J].J Phys:Condens Matter,1990,19 (2):4395-4404.
PULAY P.Ab initio calculation of force constants and equilibrium geometries in polyatomic molecules I:Theory[J].Mol Phys,1969,17(2):197-204.
SOUVATZIA P,KATSNELSON M I,SIMAK S.Firstprinciples prediction of superplastic transition-metal alloys[J].Phys Rev B,2004; 70:012201-012203.
RAMER N J,RAPPE A M.Virtual-crystal approximation that works:Locating a compositional phase boundary in Pb(Zr1-xTix) O3[J].Phys Rev B,2000,62:R743-R746.
VILLAS P,CALVERT L.Pearson's Handbook of Crystallographic data for Intermetallic Phases:2nd Edt[M].OH USA:ASM International (OH),1991.
张永刚,韩雅芳,陈国良,等.金属间化合物结构材料[M].北京:国防工业出版社,200l:120.
WASILEWSKI R J.Elastic Constants and Young's Modulus of NiAl[J].Trans TMS AIME,1966,236:455-457.
FARKAS D,MUTASA B,VAILHE C,et al.Interatomic potentials for B2 NiA1 and martensitic phases[J].Modelling Simul Mater Sci Eng,1995,3(2):201-214.
VOTER A F,CHEN S P.Accurate interatomic potentials for Ni,Al and Ni3Al[J].Proc Symp Mater Res Soc,1987,82:175-180.
RAO A I,WOODWARD C,PARTHASARATHY T A.Empirical interatomic potentials for L10 TiAl and B2 NiAl[J].Proc Symp Mater Res Soc,1991,213:125-130.
JHI S H,IHM J,LOUIE G S,et al.Electronic mechanism of hardness enhancement in transition-metal carbonitride[J].Nature,1999,6726(399):132-134.
CHEN K Y,ZHAO L R,JOHN R,et al.Alloying effects on elastic properties of TiN-based nitride[J].J Phys D:App] Phys,2003,36:2725-2729.
PUGH S F.Relations between the elastic moduli and the plastic properties of polycrystalline pure metals[J].Philos Mag,1954,45:823-843.
WANG J Y,ZHOU Y C.Polymorphism of Ti3SiC2 ceramic:First-principles investigation[J].Phys Rev B,2004,69:144108-144121.
PETTIFOR D G.Theoretical predictions of structure and related properties of intermetallics[J].Mater Sci Technol,1992,8(4):345-349.
LEVIT V I,BULI A,HU J,et al.High tensile elongation of β-NiAl single crystals at 293 K[J].Scripts Mater,1996,34(12):1925-1930.
DAROLIA R,WALSTON W S,NOEBE R,et al.Mechanical properties of high purity single crystal NiAl[J].lntermetallics,1999,7(10):1195-1202.
WüRSCHUM R,BADURA-GERGEN K,KüMMERLE EA,et al.Characterization of radiation-induced lattice vacancies in intermetallic compounds by means of positronlifetime studies[J].Phys Rev B,1996,54 (2):849-856.
PIKE L M,CHANG Y A,LIU C T.Point defect concentrations and hardening in binary B2 intermetallics[J].Acta Mater,1997,45(9):3709-3719.
{{custom_fnGroup.title_cn}}
脚注
{{custom_fn.content}}
基金
湖南省教育厅科学研究资助项目(06D002)
{{custom_fund}}
PDF(1015 KB)
({{custom_author.role_cn}}), {{javascript:window.custom_author_cn_index++;}}
