当前位置: X-MOL 学术Acta Mater. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Matrix-precipitate interface-induced martensitic transformation within nanoscale phase field approach: Effect of energy and dimensionless interface width
Acta Materialia ( IF 9.4 ) Pub Date : 2020-05-01 , DOI: 10.1016/j.actamat.2020.02.047
Anup Basak , Valery I. Levitas

Abstract Martensitic transformation induced by the matrix-precipitate interface (or other internal surfaces) for single and two martensitic variants is studied using a thermodynamically consistent multiphase phase field approach. Three order parameters are considered; two of them describe the austenite ( A ) ↔ martensite ( M ) and variant M i ↔variant M j transformations in a matrix, and the third one describes the finite width matrix - non-transforming precipitate interface. The energy of the matrix-precipitate interface reduces during A → M phase transformation from the value for energy of A -precipitate interface, γA, to value for energy of M -precipitate interface, γM, due to its dependence on the order parameter related to the austenite↔martensite transformation. Such an interface increases the temperature for barrierless martensite nucleation well above the critical temperature for A → M transformation. The nucleation temperatures strongly depend on the ratio Δ ¯ of the widths of the matrix-precipitates interface and A − M interface. New “phase diagram” for transformation temperatures between austenite, martensite, and premartensite versus Δ ¯ has been presented for neglected mechanics for two cases when magnitude of Δ γ = γ M − γ A is larger than the energy of the A − M interface (0.2 N/m). For Δ γ = − 0.5 N/m, below a critical width ratio Δ ¯ * , a layer of premartensite appears jump-like within the matrix-precipitate interface and progresses with reducing temperature, until it loses its stability and jump-like transforms to complete martensite in the entire matrix. However, for Δ ¯ ≥ Δ ¯ * , the entire matrix transforms to martensite without any premartensite. For Δ γ = − 0.3 N/m, no premartensite appears and the A matrix completely transforms into M at lower temperatures than the case with Δ γ = − 0.5 N/m. The combined effect of the energy of the matrix-precipitate interface, Δ ¯ , precipitation-induced misfit strains, and applied displacements on the boundary of the sample on nucleation of martensite and complex microstructure evolution in the systems with a single and two martensitic variant(s) is studied. Obtained results are important for controlling cyclic martensitic transformations in shape memory and elastocaloric alloys and designing alloys with desired characteristics of martensitic transformations.

中文翻译:

纳米级相场方法中基质-沉淀界面诱导的马氏体转变:能量和无量纲界面宽度的影响

摘要 使用热力学一致的多相场方法研究了由单一和两种马氏体变体的基质-沉淀界面(或其他内表面)引起的马氏体转变。考虑了三个阶次参数;其中两个描述了矩阵中的奥氏体 ( A ) ↔ 马氏体 ( M ) 和变体 M i ↔变体 M j 变换,第三个描述了有限宽度矩阵 - 非相变析出物界面。在 A → M 相变过程中,基质-沉淀界面的能量从 A -沉淀界面的能量值 γA 减少到 M -沉淀界面的能量值 γM,因为它依赖于与奥氏体↔马氏体转变。这种界面将无障碍马氏体形核的温度提高到远高于 A → M 转变的临界温度。成核温度很大程度上取决于基体-析出物界面和 A-M 界面的宽度比 Δ¯。当 Δ γ = γ M − γ A 的大小大于 A − M 界面的能量时,对于忽略力学的两种情况,已经提出了奥氏体、马氏体和预马氏体之间转变温度与 Δ¯ 的新“相图”( 0.2 牛/米)。对于 Δ γ = − 0.5 N/m,低于临界宽度比 Δ¯ * ,在基体-沉淀界面内,一层预马氏体呈跳跃状,并随着温度的降低而发展,直到失去稳定性并跳跃状转变为整个基体中的完整马氏体。然而,对于 Δ¯ ≥ Δ¯ * ,整个基体转变为马氏体,没有任何预马氏体。对于 Δ γ = − 0.3 N/m,没有预马氏体出现,并且 A 基体在比 Δ γ = − 0.5 N/m 的情况更低的温度下完全转变为 M。基体-沉淀界面的能量 Δ¯ 、沉淀诱导的错配应变和施加在样品边界上的位移对马氏体形核和具有单一和两个马氏体变体的系统中复杂微观结构演化的综合影响( s) 进行了研究。获得的结果对于控制形状记忆和弹性热合金中的循环马氏体转变以及设计具有所需马氏体转变特性的合金非常重要。没有预马氏体出现,并且 A 基体在比 Δ γ = − 0.5 N/m 的情况更低的温度下完全转变为 M。基体-沉淀界面的能量 Δ¯ 、沉淀诱导的错配应变和施加在样品边界上的位移对马氏体形核和具有单一和两个马氏体变体的系统中复杂微观结构演化的综合影响( s) 进行了研究。获得的结果对于控制形状记忆和弹性热合金中的循环马氏体转变以及设计具有所需马氏体转变特性的合金非常重要。没有预马氏体出现,并且 A 基体在比 Δ γ = − 0.5 N/m 的情况更低的温度下完全转变为 M。基体-析出界面的能量 Δ¯ 、析出诱导的错配应变和施加在样品边界上的位移对马氏体形核和具有单一和两个马氏体变体的系统中复杂微观结构演化的综合影响( s) 进行了研究。获得的结果对于控制形状记忆和弹性热合金中的循环马氏体转变以及设计具有所需马氏体转变特性的合金非常重要。研究了在具有单个和两个马氏体变体的系统中马氏体形核和复杂微观结构演变的样品边界上的应用位移。获得的结果对于控制形状记忆和弹性热合金中的循环马氏体转变以及设计具有所需马氏体转变特性的合金非常重要。研究了在具有单个和两个马氏体变体的系统中马氏体形核和复杂微观结构演变的样品边界上的应用位移。获得的结果对于控制形状记忆和弹性热合金中的循环马氏体转变以及设计具有所需马氏体转变特性的合金非常重要。
更新日期:2020-05-01
down
wechat
bug