单晶γ-TiAl合金疲劳裂纹扩展机制的原子模拟
|
摘要
为了研究TiAl合金的疲劳性能、裂纹扩展与组织形态的关系,采用分子动力学方法和速度加载的方式,对含内嵌边界裂纹的单晶γ-TiAl合金在交变载荷循环加载下,微裂纹扩展及微观形变机制进行研究。结果表明:单晶γ-TiAl合金在交变载荷的循环加载下裂纹扩展过程及微观形变机制分为三个阶段,其力学性能受加载过程中出现的裂纹尖端晶格畸变,棱柱位错滑移,Lomer-cottrell位错群形成,堆垛层错开动,形变孪晶等各种微观缺陷及其相互作用结果影响,不同阶段的裂纹扩展机理及塑性形变机制完全不同。
In order to study the relationship of fatigue property 、crack growth and organization form of TiAl alloy,the micro crack growth and micro deformation mechanism of single crystal γ-TiAl alloy with an embedded boundary crack under cyclic loading were studied by means of molecular dynamics and velocity loading. Results show that the crack growth process and micro deformation mechanism of single crystal γ-TiAl alloy under cyclic loading were divided into three stages. The mechanical properties are affected by the defects of crack tip lattice distortion,prismatic dislocation slip,Lomer-cottrell dislocation group formation,stacking fault start,deformation twin,etc. and their interaction results in the loading process. The mechanism of crack growth and the mechanism of plastic deformation at different stages were quite different. The research results provide a strong theoretical guidance for improving the performance of γ-TiAlalloys under complex external loading conditions.
In order to study the relationship of fatigue property 、crack growth and organization form of TiAl alloy,the micro crack growth and micro deformation mechanism of single crystal γ-TiAl alloy with an embedded boundary crack under cyclic loading were studied by means of molecular dynamics and velocity loading. Results show that the crack growth process and micro deformation mechanism of single crystal γ-TiAl alloy under cyclic loading were divided into three stages. The mechanical properties are affected by the defects of crack tip lattice distortion,prismatic dislocation slip,Lomer-cottrell dislocation group formation,stacking fault start,deformation twin,etc. and their interaction results in the loading process. The mechanism of crack growth and the mechanism of plastic deformation at different stages were quite different. The research results provide a strong theoretical guidance for improving the performance of γ-TiAlalloys under complex external loading conditions.
引文
[1]CHEN J H,CAO R,WANG G Z,et al.Study on notch fracture of Ti Al alloys at room temperature[J].Metallurgical and Materials Trans A,2004,35(2):439-457.
[2]LU Y H,ZHANG Y G,CHEN C Q.The fracture mechanism of a fully in fully lamellarγ-alloys through in-situ SEM observation[J].Intermetallics,2000(8):1443-1445.
[3]郑瑞廷,张永刚,陈昌麟,等.显微组织应变速率对全片层Ti Al合金室温塑性的影响[J].材料科学与工艺,2004,12(03):225-229.(ZHENG R T,ZHANG Y G,CHEN C Q,et al.The effect of microstructure and strain rate on the ambient ductility of FL Ti Al alloys[J].Materials Science&Technology,2004,12(3):225-229.)
[4]孙红亮,黄泽文,朱德贵.热处理对Ti-44A1-4Nb-4Zr-1B合金组织和性能的影响[J].热加工工艺2013,42(1):187-192.(SUN H L,HUANG Z W,ZHU D G.Effects of heat treatment on microstructure and mechanical properties of Ti Al-based alloy[J].Hot Working Technology,2013,42(1):187-192.)
[5]孙诗涵,陈华.Ti Al合金高温真空烧结组织及氧化性能研究[J].热加工工艺,2014,43(6):1-4.(SUN S H,CHEN H.High temperature vacuum sintering microstructure and oxizability of Ti Al alloy[J].Hot Working Technology,2014,43(6):1-4.)
[6]朱浩,曹睿,陈剑虹,等.不同预损伤对层状Ti Al基合金断裂行为的影响[J].稀有金属,2006,32(3):60-65.(ZHU H,CAO R,CHEN J H,et al.Effect of different pre-damage on fracture behavior of lamellar titanium aluminum alloys[J].Chinese Journal of Rare Metals,2006,32(3):60-65.)
[7]雷明霞,曹睿,陈剑虹,等.加载速率对Ti Al基合金载荷控制下的断裂机理影响[J].稀有金属材料与工程,2006,35(11):1730-1734.(LEI M X,CAO R,CHEN J H,et al.Effect of loading rate on fracture mechanism of Ti Al-Based alloys[J].Rare Metal Materials and Engineering,2006,35(11):1730-1734.)
[8]曹睿,陈剑虹,张继,等.近全层γ-Ti Al基合金室温拉伸断裂机理的研究[J].稀有金属材料与工程,2005,34(5):696-700.(CAO R,CHEN J H,ZHANG J,et al.Study on tensile fracture mechanisms ofγ-Ti Al alloys for near fully-lamellar microstructure at room temperature[J].Rare Metal Materials and Engineering,2005,34(5):696-700.)
[9]XU D S,WANG H,YANG R,et al.Point defect formation by dislocation reaction in Ti Al[J].Materials Science and Engineering,2009,3(1):1-6.
[10]TANG F L,CAI H M,BAO H W,et al.Molecular dynamics simulations of void growth inγ-Ti Al single crystal[J].Computational Materials Science,2014,84:232-237.
[11]罗德春,芮执元,付蓉,等.单晶γ-Ti Al合金中裂纹沿
[111]晶向扩展的分子动力学研究[J].功能材料,2016,47(2):2067-2071.(LUO D C,RUI Z Y,FU R,et al.Molecular dynamics researvh of crack propagation along the
[111]orientation in single crystalγ-Ti Al[J].Journal of Functional Materials,2016,47(2):2067-2071.)
[12]罗德春,芮执元,付蓉,等.单晶γ-Ti Al中孔洞位置对裂纹扩展影响的分子动力学模拟[J].功能材料,2016,47(6):6136-6141.(LUO D C,RUI Z Y,FU R,et al.Effect of holes position on single crystalγ-Ti Al alloy crack propagation based on molecular dynamics simulation[J].Journal of Functional Materials,2016,47(6):6136-6141.)
[13]ZOPE R R,MISHINY.Interatomic potentials for atomistic simulations of the Ti-Al system[J].Phys rev B,2003,68(2):366-369.
[14]曲洪磊,王宇,夏源明,等.γ-Ti Al单晶纳米杆拉伸变形的分子动力学研究[J].中国科学技术大学学报,2009,39(6):627-630.(QU H L,WANG Y,XIA Y M,et al.Molecular dynamics study on tension deformation of nano-single crystalγ-Ti Al intermetallics[J].Journal of University of Science and Technology of China,2009,39(6):627-630.)
[15]TANG F L,CAI H M,BAO H W,et al.Molecular dynamics simulations of void growth inγ-Ti Al single crystal[J].Computational Materials Science,2014,84:232-237.
[16]ANDREA P,ROBIN C B.Relation between driving energy,crack shape,and speed in brittle dynamic fracture[J].Phys Rev B,2005,72:54101-54111.
[17]THOMSON R,HSIEH C,RANA V.Lattice trapping of fracture cracks[J].Appl Phys,1971,42:3154-3160.
[18]DIENES G J,PASKIN A.Molecular dynamic Simulations of crack,KM progagation[J].Phys Chem Solid,1987,48:1015-1033.
[2]LU Y H,ZHANG Y G,CHEN C Q.The fracture mechanism of a fully in fully lamellarγ-alloys through in-situ SEM observation[J].Intermetallics,2000(8):1443-1445.
[3]郑瑞廷,张永刚,陈昌麟,等.显微组织应变速率对全片层Ti Al合金室温塑性的影响[J].材料科学与工艺,2004,12(03):225-229.(ZHENG R T,ZHANG Y G,CHEN C Q,et al.The effect of microstructure and strain rate on the ambient ductility of FL Ti Al alloys[J].Materials Science&Technology,2004,12(3):225-229.)
[4]孙红亮,黄泽文,朱德贵.热处理对Ti-44A1-4Nb-4Zr-1B合金组织和性能的影响[J].热加工工艺2013,42(1):187-192.(SUN H L,HUANG Z W,ZHU D G.Effects of heat treatment on microstructure and mechanical properties of Ti Al-based alloy[J].Hot Working Technology,2013,42(1):187-192.)
[5]孙诗涵,陈华.Ti Al合金高温真空烧结组织及氧化性能研究[J].热加工工艺,2014,43(6):1-4.(SUN S H,CHEN H.High temperature vacuum sintering microstructure and oxizability of Ti Al alloy[J].Hot Working Technology,2014,43(6):1-4.)
[6]朱浩,曹睿,陈剑虹,等.不同预损伤对层状Ti Al基合金断裂行为的影响[J].稀有金属,2006,32(3):60-65.(ZHU H,CAO R,CHEN J H,et al.Effect of different pre-damage on fracture behavior of lamellar titanium aluminum alloys[J].Chinese Journal of Rare Metals,2006,32(3):60-65.)
[7]雷明霞,曹睿,陈剑虹,等.加载速率对Ti Al基合金载荷控制下的断裂机理影响[J].稀有金属材料与工程,2006,35(11):1730-1734.(LEI M X,CAO R,CHEN J H,et al.Effect of loading rate on fracture mechanism of Ti Al-Based alloys[J].Rare Metal Materials and Engineering,2006,35(11):1730-1734.)
[8]曹睿,陈剑虹,张继,等.近全层γ-Ti Al基合金室温拉伸断裂机理的研究[J].稀有金属材料与工程,2005,34(5):696-700.(CAO R,CHEN J H,ZHANG J,et al.Study on tensile fracture mechanisms ofγ-Ti Al alloys for near fully-lamellar microstructure at room temperature[J].Rare Metal Materials and Engineering,2005,34(5):696-700.)
[9]XU D S,WANG H,YANG R,et al.Point defect formation by dislocation reaction in Ti Al[J].Materials Science and Engineering,2009,3(1):1-6.
[10]TANG F L,CAI H M,BAO H W,et al.Molecular dynamics simulations of void growth inγ-Ti Al single crystal[J].Computational Materials Science,2014,84:232-237.
[11]罗德春,芮执元,付蓉,等.单晶γ-Ti Al合金中裂纹沿
[111]晶向扩展的分子动力学研究[J].功能材料,2016,47(2):2067-2071.(LUO D C,RUI Z Y,FU R,et al.Molecular dynamics researvh of crack propagation along the
[111]orientation in single crystalγ-Ti Al[J].Journal of Functional Materials,2016,47(2):2067-2071.)
[12]罗德春,芮执元,付蓉,等.单晶γ-Ti Al中孔洞位置对裂纹扩展影响的分子动力学模拟[J].功能材料,2016,47(6):6136-6141.(LUO D C,RUI Z Y,FU R,et al.Effect of holes position on single crystalγ-Ti Al alloy crack propagation based on molecular dynamics simulation[J].Journal of Functional Materials,2016,47(6):6136-6141.)
[13]ZOPE R R,MISHINY.Interatomic potentials for atomistic simulations of the Ti-Al system[J].Phys rev B,2003,68(2):366-369.
[14]曲洪磊,王宇,夏源明,等.γ-Ti Al单晶纳米杆拉伸变形的分子动力学研究[J].中国科学技术大学学报,2009,39(6):627-630.(QU H L,WANG Y,XIA Y M,et al.Molecular dynamics study on tension deformation of nano-single crystalγ-Ti Al intermetallics[J].Journal of University of Science and Technology of China,2009,39(6):627-630.)
[15]TANG F L,CAI H M,BAO H W,et al.Molecular dynamics simulations of void growth inγ-Ti Al single crystal[J].Computational Materials Science,2014,84:232-237.
[16]ANDREA P,ROBIN C B.Relation between driving energy,crack shape,and speed in brittle dynamic fracture[J].Phys Rev B,2005,72:54101-54111.
[17]THOMSON R,HSIEH C,RANA V.Lattice trapping of fracture cracks[J].Appl Phys,1971,42:3154-3160.
[18]DIENES G J,PASKIN A.Molecular dynamic Simulations of crack,KM progagation[J].Phys Chem Solid,1987,48:1015-1033.