Experimental and theoretical investigation of precipitate coarsening rate in Z-phase strengthened steels
Artikel i vetenskaplig tidskrift, 2018

Two Z-phase strengthened 12% Cr steels were investigated: they are similar in composition, however one steel contains Nb and the other contains Ta. Z-phase precipitates (CrMN, M = Nb or Ta) provide precipitation hardening for creep resistance at 650 °C in these steels. Experimental data based on the transmission electron microscopy investigation of the size evolution of Z-phase precipitates during isothermal ageing at 650 °C show that the Ta-based Z-phase benefits from a five times smaller coarsening constant compared to the Nb-based Z-phase. Theoretical calculations show that this is attributed to the smaller diffusivity of Ta compared to Nb in the steel matrix. Besides, comparing the size of the Ta-based Z-phase precipitates in the gauge and head portion of a crept specimen, it is shown that Z-phase coarsens faster under stress.

Författare

Masoud Rashidi

Chalmers, Industri- och materialvetenskap, Material och tillverkning

Joakim Odqvist

Kungliga Tekniska Högskolan (KTH)

Lennart Johansson

Siemens

John Hald

Danmarks Tekniske Universitet (DTU)

Hans-Olof Andrén

Chalmers, Fysik, Materialens mikrostruktur

Fang Liu

Chalmers, Industri- och materialvetenskap, Material och tillverkning

Materialia

2589-1529 (ISSN)

Vol. 4 247-254

Ämneskategorier

Fysikalisk kemi

Metallurgi och metalliska material

DOI

10.1016/j.mtla.2018.09.024

Mer information

Senast uppdaterat

2019-01-09