Influence of homogenisation treatments on the hot ductility of cast ATI® 718Plus®: Effect of niobium and minor elements on liquation characteristics

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:799

Article

Singh, Sukhdeep¹  Hanning, Fabian²  Andersson, Joel² 

[1] Chalmers Univ Technol, Dept Ind & Mat Sci, SE-41296 Gothenburg, Sweden

[2] Univ West, Dept Engn Sci, SE-46181 Trollhattan, Sweden

关键词: HAZ Cracking;    Niobium;    Boron;    Segregation;    Diffusion;    Constitutional liquation of carbides;   

DOI  :  10.1016/j.msea.2020.140151

来源: Elsevier

【 摘 要 】

The hot ductility of cast ATI (R) 718Plus (R) was assessed using the Gleeble thermo-mechanical simulator after being subjected to different homogenisation heat treatments. The hot ductility deteriorated significantly after longdwell homogenisation heat treatments for 24 h at temperatures of 1120 and 1190 degrees C as compared with those treated at a short dwell time of 4 h at the same temperatures. The observed ductility deterioration was related to more extensive liquation along the grain boundaries caused by different mechanisms, e.g., liquation by solute segregation mechanism, Laves melting, constitutional liquation of MC carbides and supersolidus grain boundary melting, with the effect and extent depending on the solute changes after the homogenisation heat treatments. Furthermore, the role of Nb as the solute element and as the precipitate former, as well as the effect of minor alloying elements segregating along the grain boundaries, is discussed in connection to grain boundary liquation, which contributes to a better understanding of heat-affected zone liquation cracking susceptibility of cast ATI (R) 718Plus (R).

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