• Karimzadeh, Fathallah
• Mutschlechner, Fabian
• Hassani, Behzad
• Vallant, Rudolf
• Enayati, Mohammad Hossein
• Hassani, Kamran

Abstract

The microstructure and wear properties of AZ91C alloy<br/>were studied by performing solution annealing and then<br/>aging heat treatment, friction stir processing, and friction<br/>stir processing followed by solution annealing and aging.<br/>The heat-treated microstructure included fine dendritic<br/>grains (50 ± 14.2 lm) with a considerable dissolution and<br/>dispersion of continuous network-like b-Mg17Al12 precipitates<br/>at grain boundaries. Friction stir processing significantly<br/>refined the microstructure and grains (9 ± 2.3 lm);<br/>followed by the breaking-up and dissolution of dendrites<br/>and continuous b-Mg17Al12 precipitates. Heat treatment of<br/>the friction stir processed area resulted in excessive grain<br/>growth (175 ± 71.4 lm) and dispersion of fine b precipitates.<br/>Under a range of applied stresses (0.78 MPa,<br/>2.44 MPa and 3.66 MPa) for the wear tests, only friction stir<br/>processed samples showed improvement in wear behavior<br/>at low stress, while at the higher stresses, along with the effectiveness<br/>of other processes it was the most effective process<br/>on improving the wear resistance. Heat treatment had<br/>the most effect on improving the wear resistance at the intermediate<br/>stress; moreover, applying it on the friction stir<br/>processed area remarkably enhanced the wear resistance at<br/>all stresses. Heat treatment of the friction stir processed area<br/>also resulted in the lowest friction coefficient values during<br/>the wear test, indicating the convenience of this process for<br/>wear performance of cast AZ91C alloy. Abrasion was<br/>shown as the dominant wear mechanism.

Topics

• dispersion
• grain
• Magnesium
• magnesium alloy
• Magnesium
• wear resistance
• wear test
• precipitate
• aging
• annealing
• aging