Influence of heat treatment on the microstructure and tensile properties of Ni-base superalloy Haynes 282

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

卷:679

Article

Joseph, Ceena¹  Persson, Christer¹  Colliander, Magnus Hornqvist² 

[1] Chalmers, Dept Mat & Mfg Technol, S-41296 Gothenburg, Sweden

[2] Chalmers, Dept Phys, S-41296 Gothenburg, Sweden

关键词: Superalloy;    Heat treatment;    Carbides;    Gamma prime;    Ductility;    Strength;   

DOI  :  10.1016/j.msea.2016.10.048

来源: Elsevier

【 摘 要 】

The effect of heat treatment on the microstructure and mechanical properties of Ni-base superalloy Haynes 282 was investigated. Applying a standard two-step ageing (1010 degrees C/2 h +788 degrees C/8 h) to the as-received, mill annealed, material resulted in a the presence of discrete grain boundary carbides and finely dispersed intragranular gamma', with an average size of 43 nm. This condition showed excellent room temperature strength and ductility. The introduction of an additional solution treatment at 1120 degrees C resulted in grain growth, interconnected grain boundary carbides and coarse (100 nm) intragranular gamma'. The coarser gamma' led to a significant reduction in the strength level, and the interconnected carbides resulted in quasi-brittle fracture with a 50% reduction in ductility. Reducing the temperature of the stabilization step to 996 degrees C during ageing of the mill annealed material produced a bi-modal gamma' distribution, and grain boundaries decorated by discrete carbides accompanied by gamma'. This condition showed very similar strength and ductility levels as the standard ageing of mill-annealed material. This is promising since both grain boundary gamma' and a bi-modal intragranular gamma' distribution can be used to tailor the mechanical properties to suit specific applications. The yield strength of all three conditions could be accurately predicted by a unified precipitation strengthening model.

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