The basic equations of the representation of plasticity at an interface crack by an inclined strip yield superdislocation model are derived. With a special combination of the material properties and small-scale yieldi...The basic equations of the representation of plasticity at an interface crack by an inclined strip yield superdislocation model are derived. With a special combination of the material properties and small-scale yielding case, the problem is reduced to an algebraic equation in an unknown, the ratio of the plastic zone size. Some discussions on the limitations of this model are presented.展开更多
High-entropy alloys(HEAs)with face-centered cubic(FCC)phase such as CoCrFeMnNi or CoCrNi generally exhibit ultra-high fracture toughness but relatively low strength.In contrast,body-centered cubic(BCC)HEAs often displ...High-entropy alloys(HEAs)with face-centered cubic(FCC)phase such as CoCrFeMnNi or CoCrNi generally exhibit ultra-high fracture toughness but relatively low strength.In contrast,body-centered cubic(BCC)HEAs often display higher strengths,but the few reports on fracture toughness measurement demonstrate low toughness values.Here we show that the BCC HfNbTaTiZr refractory HEA,which possesses a combination of high strength,good tensile ductility and excellent high-temperature properties,also exhibits a remarkably high fracture toughness.By using the"single specimen"compliance method for J-integral measurement according to the ASTM E1820–17 standard,its fracture toughness K_(JIC)was experimentally determined to be 210 MPa m^(1/2),which renders this HEA among the toughest metallic materials.The excellent damage tolerance makes the HEA promising for applications as high-temperature structural materials such as in aerospace field.展开更多
基金Visiting Research Fellow in Institute of Industrial Science.University of Tokyo,supported by Japan Society for the Promotion of Science.
文摘The basic equations of the representation of plasticity at an interface crack by an inclined strip yield superdislocation model are derived. With a special combination of the material properties and small-scale yielding case, the problem is reduced to an algebraic equation in an unknown, the ratio of the plastic zone size. Some discussions on the limitations of this model are presented.
基金financially supported by the National Natural Science Foundation of China(No.51771205)Liao Ning Revitalization Talents Program(No.XLYC1808027)。
文摘High-entropy alloys(HEAs)with face-centered cubic(FCC)phase such as CoCrFeMnNi or CoCrNi generally exhibit ultra-high fracture toughness but relatively low strength.In contrast,body-centered cubic(BCC)HEAs often display higher strengths,but the few reports on fracture toughness measurement demonstrate low toughness values.Here we show that the BCC HfNbTaTiZr refractory HEA,which possesses a combination of high strength,good tensile ductility and excellent high-temperature properties,also exhibits a remarkably high fracture toughness.By using the"single specimen"compliance method for J-integral measurement according to the ASTM E1820–17 standard,its fracture toughness K_(JIC)was experimentally determined to be 210 MPa m^(1/2),which renders this HEA among the toughest metallic materials.The excellent damage tolerance makes the HEA promising for applications as high-temperature structural materials such as in aerospace field.
