RT Journal Article
T1 High-heat flux Cu-0.8Y alloys investigated by positron annihilation spectroscopy
A1 Domínguez Reyes, Ricardo
A1 Monge Alcázar, Miguel Ángel
A1 Galiana Blanco, Beatriz
A1 Ortega, Yanicet
A1 Muñoz Castellanos, Ángel
A1 Carro Sevillano, Gabriel
AB This work studies the thermal stability of the microstructure and the evolution of the defects of two high-heat flux Cu-0.8 wt%Y alloys fabricated following two alternative powder metallurgy routes. One batch was produced by direct hot isostatic pressing (HIP) consolidation of Cu-0.8 wt%Y pre-alloyed atomized powders while an additional ball milling processing step was introduced before HIP sintering for the second alloy. The stability and recovery characteristics of the vacancy type defects in these alloys in the as-produced state and after processing by severe equal channel angular pressing to achieve a refine microstructure have been investigated by positron lifetime and coincidence Doppler broadening measurements in samples subjected to isochronal annealing from room temperature to 900 °C. Microhardness measurements and electron transmission microscopy analysis have also been performed to support the results obtained from the positron annihilation spectroscopy analysis techniques. The recovery curves of the positron lifetime and S-W plots show a recovery stage in agreement with the recovery stage V for Cu. However, a full recovery is not accomplished, and a stage that reverts the previous recovery takes place after annealing above ~600 °C, that leads to the formation of very stable defects at temperatures up to 900 °C, identified as vacancy aggregates and nanocavities. The characteristic shape of the coincidence Doppler broadening indicates that the dispersed Y-O particles in the Cu matrix appear to be responsible for stabilizing the vacancy aggregates and nanocavities for temperatures above 600-700 °C.
PB Elsevier
SN 0925-8388
YR 2022
FD 2022-04-15
LK https://hdl.handle.net/10016/36397
UL https://hdl.handle.net/10016/36397
LA eng
NO This research was supported by the Spanish Ministerio de Economia y Competitividad (MINECO) in the form of Project ENE2015-70300-C3-2-R and by the Regional Government of Madrid (Spain) through TECHNOFUSIÓN(III)CM (S2018/EMT-4437), and Comunidad de Madrid (Spain) - multiannual agreement with UC3M ("Excelencia para el Profesorado Universitario" EPUC3M14) - Fifth regional research plan 2016-2020; and also Spanish Ministerio de Ciencia e Innovación through project DAMAINSOL [grant number RTI2018-101020-B-I00].
DS e-Archivo
RD 27 jul. 2024