Irradiation-induced strain localization and strain burst suppression investigated by microcompression and concurrent acoustic emission experiments

• Published in: Materials characterization 2023-05, Vol.199, p.112780, Article 112780
• Main Authors: Ugi, Dávid, Péterffy, Gábor, Lipcsei, Sándor, Fogarassy, Zsolt, Szilágyi, Edit, Groma, István, Ispánovity, Péter Dusán
• Format: Article
• Language: English
• Subjects: Acoustic methods; Ion irradiation; Localization; Micromechanics; Single crystal
• ISSN: 1044-5803
• DOI: 10.1016/j.matchar.2023.112780

[Display omitted] •Compression experiments were carried out on pristine and irradiated micropillars.•Acoustic emission was recorded concurrently during deformation.•Irradiation induced dislocation loops were found by transmission electron microscopy.•Strain bursts caused by intermittent cooperative dislocation motion were detected.•The detected acoustic events were found to match the strain bursts in both cases.•Irradiation was found to decrease strain burst sizes and acoustic activity.•Interaction of mobile dislocations and loops are undetectable by acoustic emission. Plastic deformation of microsamples is characterised by large intermittent strain bursts caused by dislocation avalanches. Here we investigate how ion irradiation affects this phenomenon during single slip single crystal plasticity. To this end, in situ compression of Zn micropillars oriented for basal slip was carried out in a scanning electron microscope (SEM). The unique experimental setup also allowed the concurrent recording of the acoustic emission (AE) signals emitted from the sample during deformation. It was shown that irradiation introduced a homogeneous distribution of basal dislocation loops that lead to hardening of the sample as well as strain softening due to dislocation channeling at larger strains. Under the loading conditions imposed in the present work, the intensity of strain bursts was found to decrease during channeling. The concurrently recorded AE events were correlated with the strain bursts and their analysis provided additional information of the details of collective dislocation dynamics. It was found that the rate of AE events decreased significantly upon irradiation, however, other statistical properties did not change. This was attributed to the appearance of new type of dislocation avalanches which is dominated by short-range dislocation-obstacle interactions that cannot be detected by AE sensors.