Abstract The martensitic transformation behavior and microstructure evolutions of the (Ni, Cu, Pd)-rich Ti49.5Ni39-xCu11.5Pdx alloys along with the change of Pd content were investigated. The Ti49.5Ni39-xCu11.5Pdx alloys are composed of orthorhombic B19 martensite and a small amount of cubic Ti2Ni-type Ti2(Ni, Cu, Pd) phase and hexagonal TiNi2-type Ti(Ni, Cu, Pd)2 phase. The λ2 is affected by the increasing Pd contents, presenting a trending towards to 1. The martensitic transformations in all the Ti49.5Ni39-xCu11.5Pdx alloys are one-step of B2–B19 transformation. There presents a downward trend of the transformation temperatures with the increase of Pd content. The thermal hysteresis has been significantly reduced by the addition of Pd. The minimum thermal hysteresis is found in the Ti49.5Ni33.5Cu11.5Pd5.5 alloy, showing a value of 4.9 °C with the scan rate of 20 °C/min. It also exhibits an excellent thermal stability that only an increment of 0.04 °C in Mp and a decrement of 0.23 °C in Ap appear through 100 thermal cycles. The effect of Pd content on the martensite transformation is decided by the combination of strengthening the matrix and improving the crystallographic compatibility of the martensite and austenite phases in the (Ni, Cu, Pd)-rich Ti49.5Ni39-xCu11.5Pdx alloys.

中文翻译：

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具有近零滞后和优异热稳定性的富含 (Ni, Cu, Pd) 的 Ti49.5Ni39-xCu11.5Pdx 合金的马氏体转变和显微组织

摘要 研究了富(Ni, Cu, Pd) Ti49.5Ni39-xCu11.5Pdx合金随着Pd含量变化的马氏体相变行为和组织演变。Ti49.5Ni39-xCu11.5Pdx合金由斜方晶B19马氏体和少量立方Ti2Ni型Ti2(Ni、Cu、Pd)相和六方TiNi2型Ti(Ni、Cu、Pd)2相组成。λ2 受 Pd 含量增加的影响，呈现趋向于 1 的趋势。所有 Ti49.5Ni39-xCu11.5Pdx 合金中的马氏体转变是 B2-B19 转变的一步。随着Pd含量的增加，转变温度呈下降趋势。通过添加 Pd 显着降低了热滞后。在 Ti49.5Ni33.5Cu11.5Pd5.5 合金中发现了最小的热滞后，显示值为 4。9 °C，扫描速率为 20 °C/min。它还表现出优异的热稳定性，通过 100 次热循环，Mp 仅增加 0.04 °C，Ap 仅下降 0.23 °C。Pd含量对马氏体转变的影响取决于强化基体和提高富(Ni, Cu, Pd) Ti49.5Ni39-xCu11.5Pdx合金中马氏体和奥氏体相的晶体相容性。