Abstract FeMnSi based shape memory alloys are considered for engineering applications such as prestressing of concrete or coupling devices. For this, a high recovery stress is desired which forms when the FeMnSi alloy is first elongated and then heated above the austenite transformation temperature under mechanical constraints. In this work, we study the impact of three different microstructural properties on the recovery stress of Fe17Mn5Si10Cr4Ni1(V,C) shape memory alloys: Precipitates, texture and grain size. Precipitates allowed varying the recovery stress in a broad range between 255 MPa and 564 MPa. A recovery stress of 564 MPa was achieved by a combination of a high materials yield strength σ0.1 of 536 MPa and a shape recovery of 14%. The [001] grain orientation with a low Schmid factor has a beneficial impact on the recovery stress due to a higher yield strength when compared with the [011] orientation. A decrease of the grain size caused a Hall-Petch strengthening but had no influence on the recovery stress. However the pseudo-elasticity increased for a decrease of grain size.

中文翻译：

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FeMnSi 基形状记忆合金中恢复应力的形成：析出物、织构和晶粒尺寸的影响

摘要 FeMnSi 基形状记忆合金被考虑用于工程应用，例如混凝土预应力或耦合装置。为此，当 FeMnSi 合金首先被拉长，然后在机械约束下加热到奥氏体转变温度以上时，需要高恢复应力。在这项工作中，我们研究了三种不同的显微组织特性对 Fe17Mn5Si10Cr4Ni1(V,C) 形状记忆合金恢复应力的影响：沉淀物、织构和晶粒尺寸。沉淀物允许在 255 MPa 和 564 MPa 之间的广泛范围内改变恢复应力。通过 536 MPa 的高材料屈服强度 σ0.1 和 14% 的形状恢复的组合实现了 564 MPa 的恢复应力。由于与 [011] 取向相比具有更高的屈服强度，具有低施密特因子的 [001] 晶粒取向对恢复应力具有有益影响。晶粒尺寸的减小导致霍尔-佩奇强化，但对恢复应力没有影响。然而，随着晶粒尺寸的减小，伪弹性增加。