We investigate the effects of the annealing microstructure on the low-cycle fatigue (LCF) life (N_f), cyclic stress behaviour and fatigue microstructure of a Fe–15Mn–10Cr–8Ni–4Si alloy that exhibits a deformation-induced transformation of austenite (γ-phase) into ε-martensite (ε-phase). The alloy rolled at 800°C was annealed at 600°C, 700°C, 800°C and 900°C to vary the grain size, the fraction of recrystallised grains and the texture intensity. Fully reversed axial strain-controlled LCF tests were conducted at total strain amplitudes, Δε_t/2, ranging from 0.007 to 0.02. The alloy showed a higher N_f than common steels and ferrous high-Mn alloys in this strain range. This type of annealing microstructure was found to impact the N_f, fatigue behaviour and deformation-induced ε-martensitic transformation (ε-MT) in the studied alloy. The fully recrystallised and weakly textured austenite formed at T ≥ 800°C facilitated the uniform development of ε-martensite under cyclic deformation and led to an increased N_f. The partially recrystallised and textured austenite-containing substructure with high dislocation density formed at T ≤ 700°C suppressed the ε-MT, retarded reversible dislocation motions in the un-recrystallised regions and moderately decreased N_f. Moreover, N_f and the deformation-induced ε-MT were observed to be less sensitive to variations in grain size.

我们研究了退火微观结构对Fe-15Mn-10Cr-8Ni-4Si 合金的低周疲劳 (LCF) 寿命 ( N _f )、循环应力行为和疲劳微观结构的影响，该合金表现出奥氏体的变形诱导转变( γ-相)转变为ε-马氏体( ε-相)。在 800°C 轧制的合金在 600°C、700°C、800°C 和 900°C 下退火以改变晶粒尺寸、再结晶晶粒的比例和织构强度。完全反向轴向应变控制 LCF 测试在总应变幅度Δε _t /2 范围内进行，范围从 0.007 到 0.02。该合金表现出更高的N _f在这个应变范围内，比普通钢和高锰铁合金。发现这种类型的退火显微组织会影响所研究合金中的N _f、疲劳行为和变形诱导的ε -马氏体转变 ( ε -MT)。在T ≥ 800°C时形成的完全再结晶和弱织构奥氏体有利于ε-马氏体在循环变形下的均匀发展，并导致N _f增加。在T ≤ 700°C形成的具有高位错密度的部分再结晶和织构奥氏体亚结构抑制了ε-MT，延缓了未重结晶区的可逆位错运动并适度降低了N _f。此外，观察到N _f和变形引起的ε -MT 对晶粒尺寸的变化不太敏感。