Elasticity Size Effect Of Nb Fiber In Composite Material

Nanowires have ultra-large elastic strain limits and ultrahigh yield strength.Materials scientists consider that the reinforced composite materials should have super high mechanical properties.However,all the existing research results are disappointing,the extraordinary mechanical properties of nanowires or nanoparticles can't be achieved in the reinforced composites.For example,freestanding nanowires have ultra-large elastic strain(4-7%),but its elastic strain in composites is limited(less than 1.8%).Recently,our research group has found that the nanowires embedded in the matrix deformed by lattice shear shows ultra-large elastic strain,and its composite materials have high mechanical properties.Macroscopic materials on the performance has the characteristic of the smaller the stronger,but because of performance of nanowires in composite material is limited,there's no further research of size effect in nanowires.On the base of this,the size effect of nanowires in composite materials is studied in this paper.The main research is as follows:We prepare two different composite materials.One is Nb/NiTi composite materials by smelting,forging,cold drawing process preparation and one is Nb/Cu composite materials by smelting,forging,beam technology.Then all wires are tested by high energy X-ray diffraction tensile to test mechanical properties of Nb fibers in the material.Found that,Nb fiber elastic strain with fiber increase with the decrease of the size,and once again to verify that the lattice shear matrix nanowires can render large elastic strain.Simple at the same time,we discuss the temperature effect on the properties of the nanowires,and found that the elastic strain of Nb nanowires has no obvious change in different temperature,presumed temperature has no use to elastic strain of Nb fiber in composite materials.