The effect of the number of passes in friction stir processing of aluminum alloy (AA6082) and its failure analysis

Abstract

Abstract Friction stir processing (FSP) is a technique based on micro-structural modification. Though this concept attracts the attention of the researchers, there arise a necessity of deep investigation in many areas to understand the changes and failure caused by the process. To achieve the required micro grain size, few process attributes like tool geometry, rotational speed, transverse speeds, etc., are to be regulated. The defects, especially tunnel voids can be greatly reduced by identifying the adequate process parameters. The reason for such defect is due to inadequate heat supply during processing and dynamic recrystallization. In this study, FSP of aluminum AA6082 alloy is performed to investigate the effect of different process parameters, such as number of passes and tool rotational speed. Mechanical and microstructure analysis of the specimens were conducted to determine the changes in the properties of the aluminum alloy. Temperature distribution was also monitored using infrared (IR) camera to determine the temperature intensity in degrees at limited points. The results show that the heat generation increases when rotational speed increases. Hardness and tensile strength were tested across the FSP processed zone. After FSP, the microstructure of the alloy is found to be exceedingly refined. However, FSP causes minuscule improves the hardness of the material, whereas the tensile and impact strength improves significantly.