关键词: EMS206合金, 时效, σ相, 力学性能, 析出相

Abstract: EMS206 alloy was heat-treated at 1160 ℃×30 min+750 ℃×4 h and then subjected to long-term aging at 750 ℃ for 50-4000 h, the microstructure was observed by means of metallographic microscope, the mechanical properties were tested by tensile testing machine, the fracture morphology was observed under scanning electron microscopy, and the intermediate phase composition of the alloy was analyzed by means of TEM. The results show that with the extension of the aging time, the grain size of the alloy does not increase significantly, and the relative contents of M₂₃C₆ and MX phases in the microstructure increase. After aging for 100 h, the M₂₃C₆ phase at grain boundary precipitates in the form of particles inside the grains, after aging for 400 h, the MX phase of intragranular precipitates increases, after aging for 1600 h, the size of the granular MX phase gradually increases, and after aging for 2400 h, the σ-FeCr phase gradually appears in the matrix. With the increase of aging time, the hardness of the EMS206 alloy decreases from 332.2 HV to 296.4 HV, and the elongation decreases from 22.8% to 8.8%.

Key words: EMS206 alloy, aging, σ phase, mechanical properties, precipitated phase