Effects of SMAT at cryogenic and room temperatures on the kink band and martensite formations with associated fatigue resistance in a β-metastable titanium alloy

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

卷:803

Article

Maurel, Pierre^1,2,3  Weiss, Laurent¹  Bocher, Philippe²  Grosdidier, Thierry^1,3 

[1] Univ Lorraine, Lab LEM 3, CNRS, UMR 7239, 7 Rue Felix Savart, F-57073 Metz, France

[2] Ecole Technol Super, Lab Optimisat Procedes Fabricat Avances LOPFA, 1100 Rue Notre Dame Ouest, Montreal, PQ, Canada

[3] LAB DEXcellence Design Alloy Met Low mAss Struct, 7 Rue Felix Savart, F-57073 Metz, France

关键词: Severe plastic deformation (SPD);    Beta titanium alloy;    High cycle fatigue;    Surface mechanical attrition treatment (SMAT);    Kink band;    Cryogenic treatment;   

DOI  :  10.1016/j.msea.2020.140618

来源: Elsevier

【 摘 要 】

Surface Mechanical Attrition Treatment (SMAT) has been carried out at cryogenic and room temperatures on a 5553 beta-metastable Ti alloy to describe its effects on the modification of the microstructure and fatigue properties. The cryogenic temperature promoted the martensitic transformation and the width of the kink bands produced by SMAT. The kink bands formation was promoted by the high strain rates of the SMAT process. The samples SMATed at cryogenic temperature showed an increase in fatigue resistance, by about 8%, compared to samples processed by SMAT at room temperature. This improvement was possibly due to a combination of several factors: compressive residual stresses, lower roughness, deeper formation of martensite and larger kink bands. On the contrary, the SMAT at room temperature did not provide any improvement in terms of fatigue compared to the polished condition. The large grain size provoked the appearance of subsurface crystallographic defects on which primary cracks initiated. This greatly limited the effectiveness of the reinforced surface layer produced by SMAT.

【 授权许可】

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