INFLUENCE OF IMPURITIES ON THE LOW-TEMPERATURE DEFORMATION OF NANOCRYSTALLINE COPPER

The influence of ZrO2 particles on the low-temperature deformation of nanocrystalline copper produced by strong plastic deformation is inves tigated using equichannel angular pressing. A comparison is made betwe en the deformation characteristics in tension and compression in the t emperature range 4.2-400 K, measured for copper and the composite Cu: 0.3 vol. % ZrO2. It is shown that within 4.2-200 K the yield point sig ma(s)m of the composite is higher than that for copper, attaining 680 MPa at 4.2 K, then the yield points are close in value up to room temp erature, and diverge again as the temperature is raised. Possible caus es of the dissimilar influence of an impurity on the strength and plas ticity characteristics of nanocrystalline copper in various temperatur e intervals are discussed. (C) 1998 American Institute of Physics. [S1 063-7834(98)01609-8].