Adhesive assisted TiB₂ coating effects on friction stir welded joints

Area of Science:

• Materials Science
• Mechanical Engineering
• Manufacturing Processes

Background:

• Friction stir welding (FSW) is a solid-state joining method for various materials.
• Groove fill techniques are common for reinforcing FSW joints, but reinforcement loss is a drawback.
• Improving the mechanical properties of FSW joints remains an active area of research.

Purpose of the Study:

• To develop an adhesive-assisted reinforcement technique to mitigate reinforcement loss during FSW.
• To investigate the effect of TiB2 coating on the mechanical properties of friction stir welded aluminum alloy joints.
• To compare the performance of coated and non-coated joints fabricated using FSW.

Main Methods:

• Aluminum alloy plates were coated with a thin layer of Titanium Diboride (TiB2).
• Coated and non-coated plates were joined using friction stir welding with a taper threaded pin tool.
• Welding parameters included rotational speeds of 1400 and 2240 rpm and a welding speed of 32 mm/min.
• Mechanical properties including tensile strength, elongation, flexural strength, impact strength, and hardness were evaluated.

Main Results:

• TiB2 coated joints exhibited a 39.74% superior tensile strength compared to non-coated joints.
• Flexural strength was approximately 1.5 times higher in TiB2 coated joints.
• Hardness increased by 22.75% in TiB2 coated joints welded at 2240 rpm.
• Percentage elongation decreased by about 1.5 times, and impact strength was nearly three times lower in coated joints.

Conclusions:

• The adhesive-assisted TiB2 coating effectively enhances tensile, flexural strength, and hardness in friction stir welded aluminum alloy joints.
• While improving strength and hardness, the TiB2 coating negatively impacts ductility (elongation) and impact toughness.
• This technique offers a viable solution to reinforcement loss in FSW, but trade-offs in other mechanical properties need consideration.