Mechanical Joining Techniques for Dissimilar Materials

Mechanical joining techniques that produce load-bearing interlocks without melting are increasingly critical for assembling lightweight and multifunctional structures across automotive, aerospace and renewable-energy sectors. By avoiding thermal input, methods such as clinching, riveting and specialised form-locked joints preserve base-material properties and minimise distortion. Clinching utilises local plastic deformation to form an interlock between sheets of differing ductility or thickness, while self-piercing riveting deploys a rivet that pierces and flares to clamp materials without pre-drilling. Friction riveting exploits a rotating tool to generate heat and plasticise thermoplastics, enabling a metallic rivet to be anchored in composite substrates. Non-adhesive form-locked joints, pin and loop joining introduce mechanical elements—pins, hooks or loops—that engage complementary features in mating parts. Flow drilling and flow-drill screws create threaded necks in ductile alloys by combining rotational motion with axial force, allowing for screw insertion directly into the workpiece. Recent advances focus on optimising tool geometry, process parameters and surface preparation to enhance joint strength, fatigue life and corrosion resistance. Hybrid approaches that integrate clinching with adhesive layers or post-joining heat treatment are emerging to address environmental sealing and durability requirements. Together, these mechanical joining strategies enable the efficient assembly of dissimilar metals, metal–polymer hybrids and fibre-reinforced composites, supporting the drive towards lighter, more sustainable transport and energy systems.

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Mechanical Joining Techniques for Dissimilar Materials publication trend

The graph below shows the total number of articles in mechanical joining techniques for dissimilar materials across all publications each year (not limited to Nature Index journals).

Technical terms

Mechanical clinching: A cold-forming process that plastically deforms overlapping sheets to create a permanent mechanical interlock without auxiliary fasteners.

Self-piercing riveting: A joining method in which a semi-tubular rivet pierces through stacked sheets and flares to clamp components, requiring no pre-drilled holes.

Friction riveting: A hybrid technique using a rotating metallic rivet to generate frictional heat, deforming thermoplastic composites and embedding the rivet tip.

Form-locked joint: A non-adhesive connection relying on complementary geometric features—such as hooks, undercuts or tabs—to resist separation.

Pin and loop joining: Methods employing solid pins or looped elements to interlock composite and metal parts by insertion into pre-formed channels or through-holes.

References

1. Mechanical Joining of Fibre Reinforced Polymer Composites to Metals—A Review. Part II: Riveting, Clinching, Non-Adhesive Form-Locked Joints, Pin and Loop Joining. Polymers (2020).
2. Preheated (Heat-Assisted) Clinching Process for Al/CFRP Cross-Tension Specimens. Materials (2020).
3. Mechanical clinching and self-pierce riveting for sheet combination of 780-MPa high-strength steel and aluminium alloy A5052 sheets and durability on salt spray test of joints. The International Journal of Advanced Manufacturing Technology (2021).
4. Mechanical Testing of Flow Drill Screw Joints Between Fibre-Reinforced Plastics and Metals. Materials Testing (2013).