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Effect of deep cryogenic treatment on microstructure, creep and wear behaviors of AZ91 magnesium alloy

Meshinchi Asl, K ; Sharif University of Technology | 2009

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  1. Type of Document: Article
  2. DOI: 10.1016/j.msea.2009.06.003
  3. Publisher: 2009
  4. Abstract:
  5. This paper focuses on the effect of deep cryogenic treatment (-196 °C) on microstructure and mechanical properties of AZ91 magnesium alloy. The execution of deep cryogenic treatment on samples changed the distribution of β precipitates. The tiny laminar β particles almost dissolved in the microstructure and the coarse divorced eutectic β phase penetrated into the matrix. This microstructural modification resulted in a significant improvement on mechanical properties of the alloy. The steady state creep rates were measured and it was found that the creep behavior of the alloy, which is dependent on the stability of the near grain boundary microstructure, was improved by the deep cryogenic treatment. For the AZ91 alloy, the results indicate a mixed mode of creep behavior, with some grain boundary effects contributing to the overall behavior. However for the deep cryogenic samples dislocation climb controlled creep is the dominant deformation mechanism. After the deep cryogenic treatment the sliding of grain boundaries was greatly suppressed due to morphological changes. As a result, the grain boundaries are less susceptible for grain boundary sliding at high temperatures. Dry sliding wear tests were also applied and the wear resistance of the alloy improved remarkably after deep cryogenic treatment. © 2009 Elsevier B.V. All rights reserved
  6. Keywords:
  7. Magnesium alloy ; AZ91 magnesium alloys ; Creep behaviors ; Deep cryogenic treatment ; Deep cryogenic treatment (DCT) ; Dislocation climb ; Dominant deformation mechanism ; Dry sliding wear test ; Grain boundary effects ; Grain boundary microstructure ; High temperature ; matrix ; Microstructural modification ; Microstructure and mechanical properties ; Mixed mode ; Morphological changes ; Steady state creep rate ; Wear behaviors ; Alloys ; Cerium alloys ; Cosine transforms ; Creep ; Discrete cosine transforms ; Dissolution ; Grain boundaries ; Grain boundary sliding ; Grain size and shape ; Magnesium ; Magnesium alloys ; Mechanical properties ; Microstructure ; Wear of materials ; Wear resistance ; Cryogenics
  8. Source: Materials Science and Engineering A ; Volume 523, Issue 1-2 , 2009 , Pages 27-31 ; 09215093 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0921509309006509