Dissimilar Metal Spot Joining with IMC-Suppressing Thickness Reduction

The patent replaces conventional thermal metallurgical joining methods with a mechanical joining approach using a press machine that applies a press load to the superposed metal materials. This mechanical pressing induces plastic flow and solid-phase diffusion at the bonding interface, achieving strong bonds without forming harmful IMC layers that occur in traditional welding or resistance spot welding processes.

The patent changes the fundamental parameters of the joining process by controlling the press load magnitude, press time duration, and surface temperature within specific ranges. By optimizing these parameters (press load: 10-1000 kN, press time: 0.1-10 seconds, temperature: room temperature to 500°C), the process achieves solid-phase bonding with minimal IMC formation, fundamentally altering the joining mechanism from thermal-metallurgical to mechanical-solid phase diffusion.

The patent extracts and eliminates the harmful IMC formation mechanism entirely by replacing thermal metallurgical joining with mechanical pressing. Instead of trying to control IMC thickness to 1-2 μm as in conventional methods, this approach prevents IMC formation at the bonding interface through solid-phase diffusion bonding, making production control straightforward and reliable without requiring precise IMC thickness management.

The patent introduces a press machine as an intermediary device that applies controlled mechanical pressure to induce plastic flow and solid-phase diffusion. This intermediary mechanical action replaces the need for thermal processes that generate IMC, providing a controllable and reproducible joining method that is easy to implement in production environments with standard press equipment.