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Effect of rare earth elements addition on thermal fatigue behaviors of AZ91 magnesium alloy

Bayani, H ; Sharif University of Technology | 2009

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  1. Type of Document: Article
  2. DOI: 10.1016/S1002-0721(08)60230-6
  3. Publisher: Chinese Society of Rare Earths , 2009
  4. Abstract:
  5. Influences of rare earth (RE) elements addition on thermal fatigue behaviors of AZ91 alloy were studied. Repeated heating and cooling cycles were applied on the samples at 170 and 210 °C to develop thermal fatigue cracks. Crack growth mechanisms and microstructural influences were investigated by optical and scanning electron microscopy (SEM) as well as energy dispersive X-ray spectroscopy (EDS). Thermal fatigue behaviors were observed to improve successively by addition of the RE up to 2wt.%. This improvement was attributed to the consummation of aluminum in melt by precipitation of the needle shaped Al11RE3 phases. This process was attributed to the reduction of Mg17Al12 phase volume fraction and consequent decrease of the brittle Mg/Mg17Al12 interface which was the main reason for weak thermal properties of the alloy at rather high temperatures. Further additions of RE, however, reduced the thermal shock resistance of the samples by increasing the mean length of the brittle needle shaped phases. © 2009 The Chinese Society of Rare Earths
  6. Keywords:
  7. Alloys ; Alumina ; Aluminum ; Cracking (chemical) ; Cracks ; Magnesium ; Magnesium alloys ; Needles ; Optical microscopy ; Phase interfaces ; Rare earth elements ; Rare earths ; Scanning electron microscopy ; Thermal fatigue ; Thermal shock ; Thermodynamic properties ; AZ91 alloy ; Az91 magnesium alloys ; Cooling cycles ; Crack-growth mechanisms ; Energy dispersive x-ray spectroscopies ; Fatigue behaviors ; High temperatures ; Microstructural influences ; Phase volume fractions ; Sem ; Thermal fatigue cracks ; Thermal properties ; thermal shock resistance ; Cerium alloys
  8. Source: Journal of Rare Earths ; Volume 27, Issue 2 , 2009 , Pages 255-258 ; 10020721 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/pii/S1002072108602306