Influence of rotational speed on mechanical and microstructural characteristics on the rotary friction welded as-cast LM25 aluminium alloy

Abstract

The cast aluminium alloys are widely used in aircraft and automobile industries as structural and component application due to its lower density, high specific strength and good corrosion resistance. In this current investigation, as-cast aluminium alloy LM25 is rotary friction welded and the effect of rotational speed on the mechanical and microstructural characteristics is analyzed. The rotational speed was varied between 900 rpm and 1300 rpm whereas other process parameters such as friction pressure and forging pressure were kept constant at 10 MPa/s. The microstructural examination was performed using optical and scanning electron microscopy and the mechanical properties were evaluated through microhardness, smooth and notch tensile tests. The results from the microstructural examination show that there is coarsening of the grains occurs when there the rotational speed is decreased due to the reduced heat input and dynamic recrystallization in the fully deformed zone (FDZ). The mechanical properties are supported by the microstructures as the tensile strength and hardness increases with an increase in rotational speed of the friction welding process.