Electrical conductivity and mechanical properties of Cu-0.7wt% Cr and Cu-1.0wt% Cr alloys processed by severe plastic deformation

6th International Conference on Nanomaterials by Severe Plastic Deformation

材料科学;化学

Kommel, L.^1 ; Pokatilov, A.^1

Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia^1

关键词: Coefficient of frictions;    Electrical conductivity;    Experimental investigations;    Post-deformation heat treatment;    Severe plastic deformations;    Tensioncompressions;    Ultrafine grained materials;    Visco-elastic behaviors;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/63/1/012169/pdf
DOI  :  10.1088/1757-899X/63/1/012169

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

As-cast Cu-0.7wt% Cr and Cu-1.0wt% Cr alloys were subjected to equal-channel angular pressing (ECAP), hard cyclic viscoplastic (HCV) deformation and post deformation heat treatment for receiving an ultrafine grained material with a combination of high strength, good wear resistance and high electric conductivity. Samples from Cu-0.7wt% Cr alloy were processed up to six passes and Cu-1wt% Cr alloy samples were processed up to four passes of ECAP via Bc route. HCV deformation of samples was conducted by frequency of 0.5 Hz for 20 cycles at tension-compression strain amplitudes of ±0.05%, ±0.1%, ±0.5%, ±1% and ±1.5%, respectively. During HCV deformation, as-cast Cu-0./wt% Cr alloy show fully viscoelastic behavior at strain/stress amplitude of ±0.05% while ECAP processed material show the same behavior at strain amplitude of ±0.1%. The Young modulus was increased from ∼120 GPa up to ∼150 GPa. The results illustrated that specific volume wear decrease with increasing of hardness but the measured coefficient of friction (COF ∼ 0.6) was approximately the same for all samples at the end of wear testing. The hardness after ECAP for 6 passes by Bc route was 192HV0.1 and electric conduction 74.16% IACS, respectively. By this the as-cast Cu-0./wt% Cr alloy (heat treated at 1000 °C for 2h) has microhardness ∼70HV0.1 and electrical conductivity of ∼40% IACS. During aging at the temperatures in the interval of 250-550 °C for 1h the hardness and electrical conductivity were stabilized to mean values of 120±5HV0.1 and to 93.4±0.3% IACS, respectively. The hardness and electric conductivity took decrease by temperature increase over ∼550 °C, respectively. The results of present experimental investigation show that UFG Cu- 0.7wt% Cr alloy with compare to Cu-1.0% Cr alloy is a highly electrical conductive and high temperature wear resistant material for using in electrical industry.