Three QCr0.5 wires with initial diameters of 7 mm

5 mm and 3 mm were cold drawn through different drawing passes with average strains of 0.05 and 0.1

respectively

to obtain the samples with different strain rate.The hardness and electrical conductivity of the samples obtained were measured and the microstructures were observed to understand the effects of initial diameter and drawing passes on microstructures and properties of QCr0.5 wires.The results show that the electrical conductivity of the cold drawn samples with different initial diameters is decreased with increasing in the strain

where the samples with 7 mm have the maximum decrement value

the samples with 5 mm are the second

and samples with 3 mm have the lowest decrement value.The electrical conductivity of the samples with different drawing passes is decreased slowly with increasing in the strain under the same initial diameter

and the hardness is increased rapidly firstly

and then decreased slowly to a constant tendency.The decrease of electrical conductivity of the samples with average strain of 0.1 is more rapid than that one with the average strain of 0.05

and it is decreased by approximately 37%

however

the hardness is always the higher

where the highest hardness can reach to 114 HV.The microstructure observation reveals that the microstructure evolution of QCr0.5 is characterized by the uneven deformation of the internal and external structure

and the deformation degree of the external structure exhibits more severe.With the deformation increase

the deformation of internal and external structure tends to be homogeneous.