What is the primary concern when joining dissimilar metal alloys in engine components?

The primary concern when joining dissimilar metal alloys in engine components is thermal expansion. Different metals have varying coefficients of thermal expansion, meaning they expand and contract at different rates when subjected to changes in temperature. This discrepancy can lead to significant mechanical stresses at the joint when the metals are heated or cooled during engine operation.

When dissimilar metals are bonded together, if one metal expands more than the other, it can result in bending, warping, or even failure of the joint over time. Ensuring compatibility in thermal expansion is crucial for the longevity and reliability of engine components, as components often operate under high temperatures and rapid cycling.

While corrosion resistance, weight distribution, and mechanical strength are also important considerations in the selection and joining of materials, they are not as critical as managing thermal expansion when dealing with metals that behave differently under temperature changes.