ICRF 2026 - 5th International Conference on INGOT CASTING, ROLLING & FORGING

The development of organic light-emitting diode (OLED) display technology has imposed increasingly stringent requirements on the thickness accuracy and synergistic control of microstructure and mechanical properties of ultrathin 4J36 Invar alloy strips used for fine metal masks (FMMs). However, as the strip thickness is further reduced, the competition between recovery and recrystallization associated with accumulated cold-rolling deformation and subsequent short-time annealing becomes increasingly complex, and the thickness-dependent annealing response remains insufficiently understood. In this study, 4J36 Invar alloy strips with different thicknesses and processing states were prepared by combining cold rolling with short-time annealing. The synergistic evolution of grain boundary characteristics, local misorientation, recrystallization behavior, texture, and mechanical properties during ultrathin processing was systematically investigated. The results indicate that, when the thickness of the 4J36 Invar alloy was further reduced from 0.11 mm to 0.04 mm, the annealing-softening mechanism changed from microstructural reconstruction dominated by extensive static recrystallization to a limited softening response governed primarily by dislocation rearrangement and limited recovery. Meanwhile, the inheritance of rolling texture and the retention of residual deformation structures further restricted the restoration of ductility. This study reveals the thickness-dependent evolution of recovery–recrystallization competition during the ultrathin processing of 4J36 Invar alloy and provides a theoretical basis for optimizing cold rolling–annealing processes and achieving coordinated regulation of microstructure and mechanical properties in ultrathin Invar strips for FMM applications.
Keywords – 4J36 Invar alloy; ultrathin strip; cold rolling; short-time annealing; static recrystallization; recovery; mechanical properties