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Pistons for high power output demand its material to possess the properties of low thermal expansion, anti-seizure, wear resistance, high thermal conductivity, high creep and fatigue strength and high strength to weight ratio. Aluminium silicon alloys has excellent characteristics as a piston material. Due to design constraints in engines for heat dissipation and engine temperatures upto 300 ° C, the need for the study on the effect of thermal behaviour of the piston alloy during engine operation becomes important. However a piston operating at 150° C with aluminum silicon alloy gradually loses its attained hardness in T6 condition and is not a constant during engine operation. This decrease in hardness of the alloy due to exposure to temperature and time is due to the phenomena called “age softening”. This phenomena occurs if the equilibrium phase diagram reveals partial solid solubility of the alloying element, at a higher temperature than at lower temperature.

Aluminium finds diverse applications in the automotive industry. However, owing to its somewhat poor mechanical properties, the metal is unsuitable for structural applications. The problem is overcome by addition of alloying elements like zinc, copper, silicon, etc. and these alloys on proper heat-treatment show substantial improvement in the mechanical properties. Further enhancement of their mechanical properties can be brought about by the addition of small percentages of zirconium, which helps in the grain refinement of the cast alloy ingots. At present for cylinder head the aluminium alloy used requires to be heat treated for a cycle time of about 15 hours (T6 condition) to achieve the desired mechanical properties. The proposed aluminium alloy, which contain microalloying element, Zirconium of about 0.12 weight %, can achieve the required mechanical properties with about five times reduced cycle time (T5 condition) only.

In the recent years, reduction of new product development time is the major challenge for all auto manufacturers to sustain in the stiff competition. Durability evaluation is one of the most time consuming element in New Product Development (NPD) process. Finding a generic solution for commonly faced design issues is a key factor for dramatic reduction in evaluation time. Testing time reduction can be achieved by breaking down the evaluation into subsystem level and component level instead of complete vehicle. But the maximum time reduction can be achieved only through durability evaluation at material / process level. This type of evaluation yields a generic solution, which results in establishing all-purpose design and material selection criteria during initial stage of development. By adopting this technique, separate evaluation of vehicles/ subsystems for improvements in material, welding, process etc. can be avoided.

Gear noise can be attributed to several reasons such as gear design parameters, gear material used etc., Owing to design, spur gears during operation produce noise. A change in gear design to helical would reduce the noise, but at the cost of an increase in friction as in operation it produces an axial thrust. A more economic and effective way of noise reduction in gears would be to go in for a material, which has good damping characteristics in order to reduce the noise levels significantly. A new member of the cast iron family, Austempered Ductile Iron (ADI), is a heat treated Spheroidal Graphite Iron(SGI). The microstructure exhibits ausferritic structure with a high volume of carbon-enriched austenite and nodular graphite. This offers the gear designer a combination of manufacturing flexibility, high strength, toughness, low weight, excellent fatigue strength and wear resistance. These properties are present along with good damping capacity and machinability.