Low cycle fatigue behavior of magnesium matrix nanocomposite at ambient and elevated temperatures

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

卷:793

Article

Jabbari, A. H.¹  Shafiee Sabet, A.²  Sedighi, M.¹  Jahed, H.³  Sommitsch, C.² 

[1] Iran Univ Sci & Technol, Sch Mech Engn, Tehran 1684613114, Iran

[2] Graz Univ Technol TU Graz, Inst Mat Sci Joining & Forming, Kopernikusgasse 24-I, A-8010 Graz, Austria

[3] Univ Waterloo, Dept Mech & Mechatron Engn, 200 Univ Ave, Waterloo, ON N2L 3G1, Canada

关键词: Magnesium matrix nanocomposite;    Low cycle fatigue;    Elevated temperatures;    Microstructural evaluations;    Mechanical properties;   

DOI  :  10.1016/j.msea.2020.139890

来源: Elsevier

【 摘 要 】

AZ31B alloy reinforced by 1.5 vol.% nano-sized Al2O3 particles has been subjected to fully-reversed straincontrolled uniaxial tension-compression cyclic loading at room temperature, 100 degrees C, and 200 degrees C. A combination of mechanical and magnetic stir casting methods followed by a hot-extrusion process was used to fabricate the composite material. Cyclic and fatigue behaviors of the composite were studied at the strain ranges of 0.8%-2.5%. The experimental results of the fatigue lives were used to assess and compare the life prediction capabilities of different existing strain-based and energy-based fatigue models. The results exhibited that the presence of the nano-sized reinforcing particles leads to a homogenously fine microstructure and slightly changes the texture of the composite extrusion, compared to the typical microstructure and texture of monolithic AZ31B extrusion. The cyclic behavior of the composite is altered from an asymmetric shape at room temperature to a symmetric one at 200 degrees C, resulting in reduction of mean stress. Unlike the room-temperature behavior, twinning and detwinning are not governing plastic deformation mechanisms at the elevated temperatures, especially at 200 degrees C. Cyclic softening occurs by increasing the temperature, in a manner similar to the monotonic tensile tests. Due to the strain-controlled loading and increasing the composite ductility at the elevated temperatures, the fatigue lives are comparable at the different temperatures. Finally, considering the results at all the temperatures, Jahed-Varvani (JV) as an energy-based model shows a more promising life prediction.

【 授权许可】

Free