Plăcintă Constantin, Nedeff Valentin, Panainte-Lehăduş Mirela, Puiu Costescu Elena, Petrescu Tudor-Cristian, Stanciu Sergiu, Agop Maricel, Mirilă Diana-Carmen, Nedeff Florin
Department of Materials Science, Faculty of Material Science and Engineering, "Gheorghe Asachi" Technical University of Iasi, Blvd. Prof. Dr. D. Mangeron, No. 41, 700050 Iași, Romania.
Department of Industrial Systems Engineering and Management, Faculty of Engineering, "Vasile Alecsandri" University of Bacau, 157, Calea Marasesti, 600115 Bacau, Romania.
Entropy (Basel). 2025 May 30;27(6):587. doi: 10.3390/e27060587.
Experimental and theoretical design on thermal and structural properties of Cu-Zn-Al alloys are established. As such, from an experimental point of view, differential thermal analysis has been performed with the help of a DSC Netzsch STA 449 F1 Jupiter calorimeter with high levels of sensitivity, and the structural analysis has been accomplished through X-ray diffraction and SEM analysis. An unusual specific property for a metallic material has been discovered, which is known as "rubber-type behavior", a characteristic determined by micro-structural changes. From the theoretical point of view, the thermal transfer in Cu-Zn-Al is presented by assimilating this alloy, both structurally and functionally, with a multifractal, situation in which the order-disorder transitions assimilated with thermal "dynamics" of Cu-Zn-Al, are mimed through transitions from non-multifractal to multifractal curves. In such a context, the thermal expansion velocity contains both the propagation speed of the phase transformation (be it a direct one: austenitic-martensitic transformation, or an indirect one: martensitic-austenitic transformation) and the thermal diffusion speed. Then, through self-modulations of the thermal field, the Cu-Zn-Al alloy will self-structure in channel-type or cellular-type thermal patterns, which can be linked to obtained experimental data. Consequently, since the thermal conductivity becomes a function of the observation scale, and heat transfer is modified to reflect the multifractal, non-differentiable paths in the material, it leads to anomalous diffusion and complex thermal behaviors.
建立了铜锌铝（Cu-Zn-Al）合金热性能和结构性能的实验与理论设计。因此，从实验角度来看，借助具有高灵敏度的耐驰（Netzsch）STA 449 F1 Jupiter量热仪进行了差示热分析，并通过X射线衍射和扫描电子显微镜（SEM）分析完成了结构分析。发现了一种金属材料的特殊性能，即所谓的“橡胶型行为”，这是一种由微观结构变化决定的特性。从理论角度来看，通过将这种合金在结构和功能上与多重分形同化来描述Cu-Zn-Al中的热传递，在这种情况下，通过从非多重分形曲线到多重分形曲线的转变来模拟与Cu-Zn-Al的热“动力学”同化的有序-无序转变。在这种情况下，热膨胀速度既包含相变的传播速度（无论是直接相变：奥氏体-马氏体转变，还是间接相变：马氏体-奥氏体转变），也包含热扩散速度。然后，通过热场的自调制，Cu-Zn-Al合金将自组织成通道型或蜂窝型热模式，这可以与获得的实验数据相关联。因此，由于热导率成为观测尺度的函数，并且热传递被修改以反映材料中多重分形、不可微的路径，这导致了反常扩散和复杂的热行为。
