Microstructure Refinement Of Heat Resistant Aluminum Alloy For Piston Application

Piston which is one of the main parts of the engine determines the engine life and running efficiency. Because piston running in the engine always works at high temperatures and pressures, so it is easy to wear and once the piston failure, the engine does not work and may even lead to the emergence of burning oil or strain cylinder because of severe carbon deposition. The materials of the piston have certain requirements. Through the reduction of grain size of piston material, can effectively improve the performance of piston alloy and prolong the life of the piston.Refiners that mentioned in this paper is Al-Ti-B intermediate alloy which is one of the most widely refiner for industrial applications. Al5Ti1 B developed by SJTU and Al5Ti1 B refining agent developed by a foreign company in our contrast research both meet the requirements of piston materials. By further research, we found that Al5Ti1 B developed by SJTU of which the Ti Al3 size is about 45 m was more well distributed and After we added the Al5Ti1 B developed by SJTU into BH135 HEAT RESISTANT ALUMINUM ALLOY as a proportion of 0.2%, the refined macrostructure was discovered. So we believed that the refining effect of Al5Ti1 B developed by SJTU is obviously better than the Al5Ti1 B refining agent developed by a foreign company mentioned in our contrast research.The study also further observed grain refinement process of BH135 piston alloy. In the actual production, we add aluminium titanium boron wire with the flow of refinement. The aluminium titanium boron wire was added by wire feeding machine, which not only played the stirring effect, but also prevented the particlesfloating hierarchical refinement. Compared to the pistons which were not added refiner, the intensity of pistons which were added refiner was increased of 8.33% at room temperature, 24.8% at 200oC, 9.6% at 300 oC, 12.76% at 350 oC. And piston elongation decreased after the addition of refiner.We do make a comparative study of Al5Ti1 B developed by SJTU and Al5Ti1 B refining agent developed by a foreign company and observed the grain refinement process of BH135 piston alloy and we do find the reduction of grain size of piston material, can effectively improve the performance of piston alloy and prolong the life of the piston.