In the present investigation, the effect of friction stir spot welding (FSSW)
parameters, typically, the tool rotation speed and dwell time on the
microstructural and mechanical characteristics offriction stir spot welds
aluminum alloy AA1050-O was investigated. The results revealed that the
width of the completely metallurgical-bonded region (CMBR) increases
with the increasing tool rotational speed and/or the dwell time up to certain
levels. Increasing the tool rotational speed and/or the dwell time above
these levels reduces the width of CMBR. Increasing the CMBR width
increases the tensile-shear strength of the friction stir joint. The maximum
tensile-shear force found in the present study was exhibited by the weld
that has the CMBR width. The peak temperature measured during FSSW
increases with increasing tool rotational speed and/or the dwell time. The
maximum peak temperature observed was about 562 oC at 1600 rpm and
14 s.