다른 압출 공정 조건에서 제조된 SEN6 마그네슘 합금의 인장 및 고주기 피로 특성 비교

초록

This study investigates the influence of extrusion parameters on the microstructure, tensile properties, and high-cycle fatigue behavior of a recently developed SEN6 magnesium alloy (Mg-6Al-0.3Mn-0.3Ca-0.2Y, wt.%). Two extrusion conditions—350 °C with an extrusion ratio (ER) of 10:1 and 400 °C with an ER of 25:1—were applied to examine the effects of temperature and applied strain on alloy performance. The high-temperature/high-ER (400-25) condition promoted complete dynamic recrystallization and resulted in coarser grains and a stronger basal texture. Despite its larger grain size, the SEN6 material extruded at the 400-25 condition exhibited superior tensile yield strength (182 MPa) and fatigue strength (110 MPa), compared to that extruded at the 350-10 condition (156 MPa and 100 MPa, respectively). Fractographic analysis revealed that fatigue cracks initiated at undissolved Al Ca particles or 2 surface slip bands. The improved mechanical properties of the former material are primarily attributed to enhanced texture strengthening that limits basal slip. These results highlight the significant role of extrusion parameters in optimizing both strength and fatigue resistance in SEN6 magnesium alloys for structural applications.

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