Abstract The effect of ageing regimes at temperatures in a range from 400 °C to 520 °C and time for up to 120 h on the spinodal decomposition of austenite in an as-quenched Mn–13Cu alloy is investigated using small-angle neutron scattering and in situ neutron diffraction. The as-quenched from 850 °C alloy has a 100% antiferromagnetic martensitic structure that can be described as a face-centered tetragonal (f.c.t.) lattice at room temperature (RT). In the early stage of the ageing process (for 8 h at 400–480 °C or for the first 16 h at 440 °C), the decomposition of the high-temperature face-centered cubic (f.c.c.) phase into an Mn-rich f.c.c. matrix and Cu-rich clusters takes place. Higher ageing temperature or longer ageing time leads to the formation of α-Mn inclusions with a body-centered cubic (b.c.c.) structure, retained after cooling to RT. Martensitic transition temperatures strongly depend on the ageing temperature and time, i.e., on the degree of chemical decomposition in austenite. The linear relationship between phase transition temperatures and Mn content in the matrix is quantitatively established. The thermal hysteresis between a direct and reverse phase transition does not change with ageing treatment. According to the in situ neutron diffraction results, structural and magnetic transitions occur at the same temperature during heating and cooling.

中文翻译：

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奥氏体的旋节线分解对 Mn-13 at %Cu 合金中马氏体转变的影响

摘要 使用小角度中子散射研究了时效制度在 400 °C 到 520 °C 的温度范围和长达 120 小时的时间对淬火态 Mn-13Cu 合金中奥氏体旋节线分解的影响。原位中子衍射。850 °C 淬火合金具有 100% 反铁磁马氏体结构，在室温 (RT) 下可描述为面心四方 (fct) 晶格。在时效过程的早期阶段（400-480 °C 下 8 小时或 440 °C 下的前 16 小时），高温面心立方 (fcc) 相分解为富锰fcc 矩阵和富铜簇发生。较高的时效温度或较长的时效时间会导致形成具有体心立方 (bcc) 结构的 α-Mn 夹杂物，并在冷却至室温后保留。马氏体转变温度很大程度上取决于时效温度和时间，即奥氏体中的化学分解程度。相变温度与基体中锰含量之间的线性关系是定量建立的。直接和反向相变之间的热滞后不随时效处理而改变。根据原位中子衍射结果，在加热和冷却过程中，结构和磁性转变发生在相同的温度。直接和反向相变之间的热滞后不随时效处理而改变。根据原位中子衍射结果，在加热和冷却过程中，结构和磁性转变发生在相同的温度。直接和反向相变之间的热滞后不随时效处理而改变。根据原位中子衍射结果，在加热和冷却过程中，结构和磁性转变发生在相同的温度。