ISSN:
1063-7834
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract The thermal stability of the yield stress and Young’s modulus was investigated in ultrafinegrained copper (99.98%) and a Cu-HfO2 composite obtained by intensive plastic deformation using the method of equichannel angular pressing. It is shown that both the pure copper and the composite strengthened with HfO2 nanoparticles demonstrate in this state a high yield stress (σ 0.2≈400 MPa). When the two-hour annealing temperature T a is increased above 200 °C, the yield stress in pure copper decreases to 40 MPa at T a=400 °C, whereas in the Cu-HfO2 composite, high yield stresses are conserved up to T a=500 °C. A recovery stage of Young’s modulus is found at around 200 °C both in pure copper and in the Cu-HfO2 composite. It is concluded that this stage reflects the transition of the grain boundaries from a nonequilibrium to an equilibrium state, and the high-strength properties of the materials are determined mainly by the grain size and depend weakly on the grain-boundary structure.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1134/1.1130509
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