caa a22 4500 388020997 CHVBK 20180307124924.0 cr unu---uuuuu 161130e199803 xx s 000 0 eng 10.1557/JMR.1998.0079 doi S0884291400043168 pii (NATIONALLICENCE)cambridge-10.1557/JMR.1998.0079 Quantitative analysis of microstructures produced by creep of Ti-48Al-2Cr-2Nb-1B: Thermal and athermal mechanisms [Elektronische Daten] A γ-based TiAl alloy with equiaxed microstructure and fine grain size has been studied to analyze the deformation mechanisms responsible for the creep behavior. The microstructures produced by creep and high temperature deformation have been examined by TEM to obtain information about the different aspects characterizing the primary and secondary stages of creep. Mechanical twinning has been confirmed to occur in a fraction of the grains that never exceeds 50% while 1/2 ‹110› dislocations are active within all the γ grains. The twins are only responsible for a small amount of strain, but they lead to a subdivision of the microstructure and determine (directly or indirectly) the hardening process observed during the primary stage of creep. We have proposed that during the secondary stage the creep rate is determined by the unblocking of pinned dislocations by processes such as a pipe diffusion or cross slip that allow thermally activated glide of 1/2‹110› dislocations on (001) planes. Copyright © Materials Research Society 1998 Morris M. A. Institute of Structural Metallurgy, University of Neuchêtel, Av. Bellevaux, 51, 2000 Neuchêtel, Switzerland Leboeuf M. Institute of Structural Metallurgy, University of Neuchêtel, Av. Bellevaux, 51, 2000 Neuchêtel, Switzerland Journal of Materials Research Cambridge University Press 13/3(1998-03), 625-639 0884-2914 13:3<625 1998 13 JMR https://doi.org/10.1557/JMR.1998.0079 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1557/JMR.1998.0079 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Morris M. A. Institute of Structural Metallurgy, University of Neuchêtel, Av. Bellevaux, 51, 2000 Neuchêtel, Switzerland NATIONALLICENCE 700 1- Leboeuf M. Institute of Structural Metallurgy, University of Neuchêtel, Av. Bellevaux, 51, 2000 Neuchêtel, Switzerland NATIONALLICENCE 773 0- Journal of Materials Research Cambridge University Press 13/3(1998-03), 625-639 0884-2914 13:3<625 1998 13 JMR CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge