Tilt angle impact on strength, microstructure of friction stir welded AZ91CMg plates

The role of tilt angle on strength and microstructural attributes of friction stir welded AZ91C Mg plates was investigated by employing three tilt angles. The presence of unique semicircular-shaped impressions on the surface of the joints attained at 1° tilt angle revealed the generation of ideal heat volume and transfer of plasticised metal towards the trailing end for attaining enhanced fusion. Zone of nugget of the joint obtained during 1° tilt angle, possessed smaller sized grain structures. The strength of joints escalated from 188 to 205 MPa (nearly 86% of the parent metal) when tilt angle was raised from 0° to 1°. But at 2° of tilt angle, strength reduced drastically, declaring the impact of tilt angle is a parabolic category of variation.