Small punch creep testing of thermally sprayed Stellite 6 coating: A comparative study of as-received vs post-heat treatment

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

卷:749

Article

Jackson, G. A.¹  Bai, M.²  Pala, Z.³  Hussain, T.¹  Sun, W.¹ 

[1] Univ Nottingham, Fac Engn, Univ Pk, Nottingham NG7 2RD, England

[2] Univ Sheffield, Dept Mat Sci & Engn, Sheffield S1 3JD, S Yorkshire, England

[3] GE Aviat, Beranovych 65, Prague, Czech Republic

关键词: Small punch creep;    HVOF;    Stellite 6;    Creep;    Fracture;    Mechanical properties;   

DOI  :  10.1016/j.msea.2019.02.030

来源: Elsevier

【 摘 要 】

Thermally sprayed Stellite 6 coatings offer high wear and corrosion-erosion resistance at high temperature but the creep behaviour of such coatings is not well understood. In this paper, the microstructure and creep behaviour of a HVOF Stellite 6 coating was investigated. The coating was tested in the as-sprayed condition and after an isothermal heat-treatment of 1 h at 1050 degrees C. The as-sprayed coating comprised FCC Co-Cr-W solid solution with 2-3 wt% HCP phase, whereas the heat-treated coating comprised FCC Co-Cr-W solid solution, 11 wt % M23C6 carbides and 7 wt% M7C3 carbides. Small punch creep tests were conducted at 700 degrees C on the as-sprayed and heat-treated coatings. The heat-treated coating exhibited minimum steady-state strain rates approximately 2 orders of magnitude lower than the as-sprayed coating when tested at similar loads, leading to times to failure approximately two orders of magnitude longer for the heat-treated coating within the selected load range. Fracture analysis showed cracking along powder particle boundaries was the main mode of cracking in the as sprayed coating whereas for the heat-treated coating, fracture along the carbide / matrix interface was the main fracture mechanism.

【 授权许可】

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