Elastic-like deformation and elastocaloric effect of a partly ordered iron-platinum alloy exhibiting a weak first-order martensitic transformation
Elastic-like deformation and elastocaloric effect of a partly ordered iron-platinum alloy exhibiting a weak first-order martensitic transformation
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DOI：
10.1088/1361-6463/aa82f3
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发表时间：
2017-09
期刊：
影响因子：
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通讯作者：
T. Fukuda;T. Kakeshita
中科院分区：
文献类型：
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作者：
T. Fukuda;T. Kakeshita
本文研究了序度为S=0.75的L12型Fe_3PT合金的类弹性形变和热弹效应的温度依赖性，该合金在85K(Tm)附近有弱的一级马氏体相变(MT)。在[001]方向施加压应力的应力-应变曲线显示，由于应力诱发MT，在TM附近有一个小阶段。相变应变在Tm为0.17%，随温度的降低而线性减小，在130K时消失，在20 Mpa，130K的应力-温度相图中为MT的临界点。由Clausius-Clapeyron方程估算出MT的潜热为0.52J·−~(-1)。在90K时，由潜热引起的绝热温度变化Δ为0.04K，而当外加应力为100兆帕时，实验测得的ΔT在90K时约为1K。对ΔT的主要贡献是软化引起的弹性应变与温度的关系，288K时的杨氏模数为55 GPa.随着温度的降低，杨氏模数呈线性下降，斜率为0.28 GPaK−1.
We have studied the temperature dependencies of elastic-like deformation and the elastocaloric effect in an L12-type Fe3Pt alloy with degree of order S = 0.75, which exhibits a weak first-order martensitic transformation (MT) near 85 K (TM). The stress–strain curve under a compressive stress applied in the [0 0 1] direction shows a small stage in the vicinity of TM due to the stress-induced MT. The transformation strain is 0.17% at TM; it decreases linearly as temperature decreases and disappears at 130 K. Thereseems to be a critical point of the MT in the stress–temperature phase diagram at (20 MPa, 130 K). The latent heat of the MT is estimated to be 0.52 J mol−1 from the Clausius–Clapeyron equation. The adiabatic temperature change ΔTadi caused by the latent heat is 0.04 K at 90 K. In contrast, experimentally obtained ΔT is approximately 1 K at 90 K when the applied stress is 100 MPa. The main contribution to ΔT is the temperature dependence of elastic strain caused by softening; the Young’s modulus at 288 K is 55 GPa and it decreases linearly with a slope of 0.28 GPa K−1 as temperature decreases.