{'fraction_non_alphanumeric': 0.02681992337164751, 'fraction_numerical': 0.017879948914431672, 'mean_word_length': 5.479338842975206, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Stress relaxation in ultrafine-grained copper at low homologous temperatures

The temperature and rate sensitivity of the flow stress in ultrafine-grained (UFG) copper prepared by equal-channel angular hydroextrusion was studied. Tensile tests and stress relaxation tests were carried out in the temperature range of 77 to 295 K. It was established that, with increasing temperature, the flow stress decreases monotonously, and the activation volume reaches a maximum of ∼190b3 at a temperature of ∼(200 ± 20) K. The results of the experiment are discussed in terms of two thermally activated plastic deformation mechanisms, namely the intersection of “forest” dislocations and dynamic recovery, which are capable of significantly distorting stress relaxation kinetics in UFG copper.