In this study, a typical dual-phase Zr alloy (Zr-2.5Nb) was subjected to β-solution treatment at 1000°C for 10 min and then cooled down to room temperature at different rates (in water (WC), air (AC) and furnace (FC)). Microstructural characteristics of the specimens were thoroughly analyzed by jointly using electron backscatter diffraction (EBSD), electron channeling contrast (ECC) imaging, X-ray diffraction (XRD) techniques and transmission electron microscopy (TEM). Specimen hardnesses were measured by a Vickers indentation tester and well correlated with the revealed microstructural characteristics. Results show that the initial dual-phase microstructure is replaced by twinned martensite, basket-weave structure and lenticular Widmanstätten structure after water cooling, air cooling and furnace cooling, respectively. Internal twins in the WC specimen are determined to be $\left\{10\overline{1}1\right\}$ compressive twinning, while inter-plate films in AC and FC specimens are Nb-enriched residual β phases. Orientation analyses show that the α phase exhibits the Burgers misorientation characteristics in all the β-cooled specimens and a single β orientation can give birth to all 12 α variants at relatively high cooling rates (both in water and air). Hardness analyses reveal that faster cooling always results in higher hardness, increasing from 216.5 HV of the FC specimen to 285.9 HV of the WC specimen (harder than the as-received material (221.9 HV)). Such variation is related to hardening contributions from specific microstructural (grain refinement, nanotwins, and solid solution) and orientation characteristics (angles between c-axes of α grains and the loading direction).

在这项研究中，典型的双相 Zr 合金（Zr-2.5Nb）在 1000°C 下进行 10 分钟的 β 固溶处理，然后以不同的速率（在水（WC）、空气（ AC）和熔炉（FC））。通过联合使用电子背散射衍射 (EBSD)、电子通道对比 (ECC) 成像、X 射线衍射 (XRD) 技术和透射电子显微镜 (TEM)，对样品的微观结构特征进行了彻底分析。试样硬度由维氏压痕测试仪测量，并与显微结构特征密切相关。结果表明，初始双相组织分别在水冷、空冷和炉冷后被孪晶马氏体、篮状组织和透镜状Widmanstätten组织取代。$\left\{10\overline{1}1\right\}$压缩孪晶，而 AC 和 FC 试样中的板间膜是富含 Nb 的残余 β 相。取向分析表明，α 相在所有 β 冷却试样中都表现出 Burgers 错误取向特征，并且单个 β 取向可以在相对较高的冷却速率下（在水中和空气中）产生所有 12 种 α 变体。硬度分析表明，较快的冷却总是导致更高的硬度，从 FC 试样的 216.5 HV 增加到 WC 试样的 285.9 HV（比接收材料（221.9 HV）更硬）。这种变化与来自特定微观结构（晶粒细化、纳米孪晶和固溶体）和取向特性（α 晶粒的 c 轴与加载方向之间的角度）的硬化贡献有关。