EFFECT OF TOOL TILT ANGLE ON MICROSTRUCTURAL CHARACTERISTICS OF FRICTION STIR WELDED LAP JOINTS OF AA2014-T6 ALUMINUM ALLOY JOINTS
Keywords:
Aluminum alloy, Friction stir lap welding, Tool tilt angle, tensile propertiesAbstract
The high strength aluminum alloys such as 2xxx and 7xxx series are suitable for parts and structure requiring high strength to weight ratio and are commonly used in aircraft fuselage and wing skins. The structures are conventionally joined by rivets. It is difficult to join these aluminum alloys especially 2xxx series by fusion welding processes due to break up of oxide layer which usually result in solidification cracking, burn through and porosity. Hence to overcome such problems solid state welding technique is chosen. Friction stir welding (FSW) is one such promising process, which can be effectively applied to weld these alloys for aircraft application with lap joint configuration. In this present investigation, the aluminum alloys 2014 were lap welded by friction stir welding technology. Effect of tool tilt angle on tensile shear fracture load (TSFL) and microstructure properties were studied experimentally. In this present study, the tool tilt angle was varied from 0° to 4° with an interval of 1o while other parameters such as tool rotational speed, welding speed, tool shoulder diameter were kept constant. Tensile shear fracture load, macro and microstructure analysis were performed to evaluate the joint strength. This investigation revealed that defect free friction stir lap welding (FSLW) was achieved by while using tool tilt angle of 1°, 2 °and 3°. However, maximum TSFL of 14.42 kN was exhibited by the joint fabricated using a tool tilt angle of 3° and the results are discussed in detail.
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