Riyadh A. Badr
University of Samarra, Iraq
Title: Tribological characteristics of hypoeutectic A383 and hypereutectic A390 (Al-Si) alloys
Biography
Biography: Riyadh A. Badr
Abstract
Hypoeutectic and hypereutectic Al-Si alloys are widely used in the automotive and aerospace, as they have interesting properties such as excellent wear resistance, high strength to weight ratio and low coefficient of thermal expansion, corrosion resistance, excellent fluidity and good casting. The piston and engine blocks made of hypereutectic alloys such as A390 were under production. However the surface of piston and engine blocks had machinability problems because of the presence of large and hard primary silicon particles. The potential savings from replacing the hypereutectic Al-Si alloys can be realised through cost savings from machining as in the hypoeutectic Al-Si alloys does not have primary silicon particles which result in high tool wear during machining. Replacing the Al-Si alloy engine block with cast iron liners with a monolithic design made of eutectic Al-Si alloys can save weight of the engine block. In addition, many expensive commercial solutions have been developed over the years. Thus, development of hypoeutectic Al-Si alloys such as A383 alloys linerless engines to overcome the costs of production of pistons and engine blocks of hypereutectic Al-Si alloys. This has created a need to understand the tribological properties of hypoeutectic Al-Si alloy at lubricated friction conditions at low loads that simulate the microstructural evolution during normal engine operation and can be a potential replacement of the expensive hypereutectic Al-Si alloys. Therefore, the study of the tribological performance is of great importance in order to optimize the properties of piston alloy for automotive engines. However, all of the tribological properties of Al-Si alloys and sliding depend on many factors, such as normal load, sliding speed, and test geometry, surface hardness, surface roughness, operating conditions.
Current research seeks to achieve the following objectives:
1. To investigate the effects of surface roughness and ultra-mild wear mechanisms of Al-Si alloys at 25 °C in order to compare the characteristics of the mechanical properties of Al-Si alloys.
2. To investigate the effect of dry and lubricated sliding condition of Al-Si Alloys, silicon content and particle size on the tribological properties of Al-Si alloys.
3. To evaluate the effect of heat treatment in Al-Si alloys.
4. To develop a surface hardness using spraying in the Al-Si alloys.
5. To evaluate the behavior of the effect of nanometric tungsten disulphide (WS2) nanoparticles in the conventional oil and the tribology behavior of hypo-and hyper-eutectic Al-Si alloys under severe contact conditions