Abstract




 
   

IJE TRANSACTIONS A: Basics Vol. 32, No. 1 (January 2019) 110-115    Article in Press

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  EFFECTS OF VARIOUS AGEING HEAT TREATMENTS ON MICROSTRUCTURAL FEATURES AND HARDNESS OF PISTON ALUMINUM ALLOY
 
M. Azadi, S. Rezanezhad and M. Zolfaghari
 
( Received: November 03, 2018 – Accepted: January 03, 2019 )
 
 

Abstract    Piston aluminum alloys have different intermetallic phases, such as Cu3Al, Mg2Si and AlNi phases. Besides, the morphology and the distribution of such phases have important roles on mechanical properties of the piston material. Therefore, in this research, various ageing heat treatments were done on the mentioned material and the microstructural feature and the hardness were studied. Obtained results showed that solutioning at 515 °C for 7 hrs and ageing at 205 °C for 7 hrs, was the superior heat treatment process, since such treatment led to increase the hardness value to its highest value (153 BHN) for the piston aluminum alloy. This heat treatment caused to increase the size of Si particles obviously and caused to precipitate other intermetallic phases of Al (Ni,Cu) and Ni-Si. Additionally, solutioning at 500 °C for 5 hrs and ageing at 180 °C for 9 hrs resulted in coarsening Si and Al-Ni participates in the longitudinal direction, which was caused to increase the hardness value to 137 BHN. EDS results indicated that when the specimen aged at 230 °C for 5 hrs, other intermetallic phases such as Al (Ni,Si) and Mg2Si were appeared in the matrix.

 

Keywords    Aluminum alloy, Piston, Heat treatment, Microstructure, Hardness

 




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