Forged piston

Abstract

To provide a forged piston made of an aluminum alloy which is excellent in heat resistance and abrasion resistance and the lightening of which is enabled. A forged piston made of an aluminum alloy is provided including 8 to 18 wt % of Si, 0.5 to 3 wt % of Cu and 1 to 5 wt % of Ni, further including Al and unavoidable impurities, in which more Ni is included than Cu and the maximum length of an intermetallic compound generated by Al and Ni is 3 to 100 μm.

1 . A forged piston made of an aluminum alloy, comprising: 
 8 to 18 wt % of Si;    0.5 to 3 wt % of Cu; and    1 to 5 wt % of Ni, further comprising:    Al; and    unavoidable impurities, wherein:    more Ni is included than Cu; and    the maximum length of an intermetallic compound generated by Al and Ni is 3 to 100 μm.    
   
   
       2 . A forged piston made of an aluminum alloy, comprising: 
 8 to 18 wt % of Si;    0.5 to 3 wt % of Cu;    1 to 5 wt % of Ni; and    2.0 wt % or less of Fe, further comprising:    Al; and    unavoidable impurities, wherein:    the total of Ni and Fe is more than Cu and is equivalent to 5 wt % or less; and    the maximum length of an intermetallic compound generated by Al, Ni and Fe is 3 to 100 μm.    
   
   
       3 . A forged piston according to  claim 1 , wherein: 
 the aluminum alloy further includes 2.0 wt % or less of Mg.    
   
   
       4 . A forged piston according to  claim 1 , wherein: 
 the aluminum alloy further includes at least either of 0.25 wt % or less of Zr, or 0.25 wt % or less of Ti; and    the total of Zr and Ti in the case where Zr and Ti are both included is equivalent to 0.3 wt % or less.    
   
   
       5 . A forged piston according to any of  claim 1 , wherein: 
 the aluminum alloy further includes at least either of 2.0 wt % or less of the total of Fe and Mn, or 2.0 wt % or less of the total of Fe and Cr×5.    
   
   
       6 . A forged piston according to any of  claim 1 , wherein: 
 the particle size of eutectic Si and pro-eutectic Si in metallographic structure of the aluminum alloy is 10 to 100 μm.    
   
   
       7 . A forged piston according to  claim 2 , wherein: 
 the aluminum alloy further includes 2.0 wt % or less of Mg.    
   
   
       8 . A forged piston according to  claim 2 , wherein: 
 the aluminum alloy further includes at least either of 0.25 wt % or less of Zr, or 0.25 wt % or less of Ti; and    the total of Zr and Ti in the case where Zr and Ti are both included is equivalent to 0.3 wt % or less.    
   
   
       9 . A forged piston according to any of  claim 2 , wherein: 
 the aluminum alloy further includes at least either of 2.0 wt % or less of the total of Fe and Mn, or 2.0 wt % or less of the total of Fe and Cr×5.    
   
   
       10 . A forged piston according to any of  claim 2 , wherein: 
 the particle size of eutectic Si and pro-eutectic Si in metallographic structure of the aluminum alloy is 10 to 100 μm.