Effect of aging on microstructures and properties of Mo-alloyed Fe-36Ni invar alloy

摘要

The Mo-alloyed invar alloy was prepared and its microstructures, mechanical properties, and thermal expansion behavior were investigated. It was found that precipitation of the Mo_2C secondary phase could be tailored by adjusting the aging processes, accordingly, the highest strength of 820 MPa and good elongation of 35%, together with a low coefficient of thermal expansion (CTE) value of 3.37 × 10~(-6)/℃ were obtained upon solution-treated at 1050 ℃ for 1 h and then aged at 525 ℃ for 3 h. The aggregation and growth of the Mo_2C secondary phase at the grain or sub-grain boundaries of the austenite could be observed with the increase of the aging time, resulting in deterioration in strength and thermal expansion of the materials.