Collaboratively enhancing the strength and ductility of GH3600 Nickel-Based Ultra-Thin strips via the Pre-Precipitation process

Abstract

Here, the effects of pre-precipitation annealing on the microstructural evolution and room-temperature mechanical properties of nickel-based ultra-thin strips after the subsequent high-temperature annealing were analyzed. By pre-precipitation annealing, discontinuous grain-boundary carbide was introduced into the cold-rolled 67 μm GH3600 nickel-based ultra-thin strips, which hindered the rapid migration of grain boundaries. Thus, the grain size was maintained at only 5.5 μm after holding at 1050 °C for 1 h, indicating that the high-temperature microstructure stability of the strips was significantly improved. Further, the phenomenon of local single-layer crystal and size effect caused by the abnormal coarsened grains, which were more than 100 μm in size during the single-stage high-temperature annealing (1050 °C for 1 h), was eliminated. Owing to the weakened free surface influence and an increase in the strengthening effect, such as grain boundary strengthening, as well as intragranular and intergranular back stress strengthening, the work hardening ability of the strips was enhanced after pre-precipitation annealing, thereby resulting in excellent comprehensive mechanical properties whose flow stress and elongation were 1.9 and 4.8 times those of single-stage high-temperature annealing. This study successfully provides an economical and easy-to-implement effective method to prepare solid-solution-strengthened high-performance ultra-thin superalloy strips.

Keywords

• Nickel-based alloys
• Ultra-thin strip
• Pre-precipitation annealing
• Size effects
• Microstructure
• Comprehensive mechanical properties