Some investigations on mechanical and metallurgical properties of Friction Stir Welded joints of AA 6101 alloy

Abstract

In 1991 a solid state joining process named friction stir welding was developed and this technique has
attracted considerable interest from the aerospace and automotive industries, since it is able to produce defect free joints
particularly for light and difficult to weld alloys i.e. magnesium and aluminum alloys. The selected material was welded
using combination of different parameters i.e. tool rotational speed (900 rpm, 1400 rpm and 1900 rpm) and welding
speed (20 mm/min, 35 mm/min and 50 mm/min). Tensile strength increases with the increase of welding speed from 20
mm/min to 50 mm/min. with increase of tool rotational speed from 900 rpm to 1400 rpm the ultimate tensile strength
increases but at 1900 rpm the ultimate tensile strength decreases. The optimum value of tensile strength is 199 N/mm2
.
The impact energies increases in friction stir welded material with respect to base metal and its optimum value is 39J.
Microstructure reveals that the hardening precipitates more dissolves at welding speed of 50 mm/min and tool rotational
speed of 1400 rpm as compared to other selected parameters.