【新文速递】2023年12月31日复合材料SCI期刊最新文章_ACT_Mechanical_System_Inspire_Deform_疲劳_复合材料_碰撞_非线性_燃料电池_航天_船舶_海洋_裂纹_理论_材料

【新文速递】2024年1月1日固体力学SCI期刊最新文章

今日更新：Mechanics of Materials 1 篇，International Journal of Plasticity 2 篇，Thin-Walled Structures 1 篇Mechanics of MaterialsEffect of the sonic shock wave on void evolution in materials under irradiationNing Zhou, YinBo Zhu, HengAn Wudoi:10.1016/j.mechmat.2023.104907 声波冲击波对辐照下材料空隙演变的影响Understanding the void-cascade interaction is of great importance for clarifying the irradiation damage as a major challenge in nuclear industry, since it typically causes void annihilation or shrinkage, which greatly affects the swelling of irradiated materials. But the current understanding of it is extremely limited due to the neglect of the sonic shock wave. Herein, we take γ-U as the representative model due to the emergence of a violent sonic shock wave there. Molecular dynamics simulations are performed to explore the underlying mechanism of the sonic shock wave interacting with voids. It is firstly revealed that the sonic shock wave is essentially focusons along <111> crystal orientation family, attributed to the highest energy transfer efficiency along <111> in γ-U. These focusons can cause void annihilation or shrinkage via sliding, while thermal spikes only cause annihilation by covering voids. Combining these two factors, we propose a model to qualitatively epitomize the void-cascade interaction, in which the influence scope exhibits an intriguing anisotropic feature, overturning a long-accepted view that the void-cascade interaction is isotropic. This model is further generalized to other nuclear materials owing to the similar mechanism of the sonic shock wave. Moreover, we find distinct size effect of voids on void-cascade interaction. Thermal spikes hardly affect voids that are too large to be covered, while the sonic shock wave also causes visible shrinkage in large voids. The present work proves that the sonic shock wave has a non-negligible effect on void evolution, improving the fundamental understanding of void-cascade interaction in irradiated materials.空隙-级联相互作用通常会导致空隙湮灭或收缩，从而极大地影响辐照材料的膨胀，因此了解空隙-级联相互作用对于澄清辐照损伤这一核工业领域的重大挑战具有重要意义。但由于忽视了声波冲击波，目前对它的认识极为有限。在此，我们以γ-U 为代表模型，因为那里出现了剧烈的声波冲击波。通过分子动力学模拟来探索声波冲击波与空隙相互作用的内在机理。研究首先揭示了声波冲击波本质上是沿 <111> 晶向系列的焦子，这归因于在 γ-U 中沿 <111> 晶向的能量传递效率最高。这些聚焦子可以通过滑动造成空隙湮灭或收缩，而热尖峰只能通过覆盖空隙造成湮灭。结合这两个因素，我们提出了一个模型来定性地表征空隙-级联相互作用，其中的影响范围呈现出令人感兴趣的各向异性特征，推翻了长期以来公认的空隙-级联相互作用各向同性的观点。由于音速冲击波的机制类似，这一模型还可进一步推广到其他核材料。此外，我们还发现空隙的大小对空隙-级联相互作用有明显的影响。热尖峰几乎不会影响大到无法覆盖的空隙，而声波冲击波也会导致大空隙的明显收缩。本研究证明了声波冲击波对空隙演变具有不可忽视的影响，从而提高了对辐照材料中空隙-级联相互作用的基本认识。International Journal of PlasticityAchieving exceptional work-hardening capability of additively-manufactured multiphase Fe-Mn alloys via multiple deformation mechanismsPeifeng Liu, Qinyuan Huang, Quan Shan, Zengbao Jiao, Qingge Wang, Yang Ma, Runhua Zhou, Ian Baker, Hong Wudoi:10.1016/j.ijplas.2023.103871 通过多种变形机制实现快速成型多相铁-锰合金的超强加工硬化能力Laser-powder-bed-fusion (LPBF) fabricated Fe-Mn biodegradable alloys provide an attractive prospect for orthopedic applications due to their good tensile strength and high degradation rate. Nevertheless, the ε-martensite and heterogeneous microstructures produced by the LPBF processing often lead to premature failure of alloys. Herein, we report a LPBFed multiphase Fe-18Mn alloy (γ-austenite, ε-martensite, and α-ferrite) fabricated from pre-alloyed powders. After annealing at 650 °C, the alloy with a uniform microstructure displays a high 1 GPa tensile strength, a good fracture elongation of 16 %, and an extremely high work-hardening rate of 8500 MPa. The work-hardening rate is higher than that reported in most Fe-Mn steels and Fe-based high entropy alloys. The grain size of a few hundred nanometers provided the excess Gibbs free energy, resulting in an increase in the stacking fault energy (SFE) to 23.9 mJ/m2. The multiple deformation mechanisms, i.e., SFs, the martensitic transformation (γ → ε → α') and nano-deformation twins (DTs), were sequentially activated. We elucidate such unique work-hardening capability, originating from the interaction between the DTs, SFs and transformed martensite. Besides a high-density of dislocations were accumulated between parallel planar defects, the cooperative deformation of the soft and hard phases provided continuous hardening. Our findings highlight the exceptional work-hardening capability of additively-manufactured Fe-Mn alloys achieved by a multiphase material exhibiting multiple deformation mechanisms. The work also provides a straightforward approach for the development of stable-implanted Fe-based bone substitutes.激光粉末床熔融（LPBF）制造的铁锰生物可降解合金具有良好的抗拉强度和较高的降解率，为矫形外科应用提供了诱人的前景。然而，LPBF加工过程中产生的ε-马氏体和异质微结构往往会导致合金过早失效。在此，我们报告了一种由预合金化粉末制成的 LPBFed 多相铁-18Mn 合金（γ-奥氏体、ε-马氏体和 α-铁素体）。在 650 °C 退火后，具有均匀微观结构的合金显示出较高的 1 GPa 抗拉强度、16 % 的良好断裂伸长率和 8500 MPa 的极高加工硬化率。该加工硬化率高于大多数铁锰钢和铁基高熵合金的加工硬化率。几百纳米的晶粒尺寸提供了过剩的吉布斯自由能，导致堆叠断层能（SFE）增加到 23.9 mJ/m2。多种变形机制，即 SFs、马氏体转变（γ → ε → α'）和纳米变形孪晶（DTs）依次被激活。我们阐明了这种独特的加工硬化能力，它源于 DTs、SFs 和转化马氏体之间的相互作用。除了在平行平面缺陷之间积累了高密度位错之外，软硬相的协同变形还提供了持续硬化。我们的研究结果凸显了加成法制造的铁锰合金通过表现出多种变形机制的多相材料实现的卓越加工硬化能力。这项研究还为开发稳定的植入式铁基骨替代物提供了一种直接的方法。Distinct avalanche dynamics detected in metallic glasses with high energy state revealing the crack-like shear banding mechanismKai Tao, Fucheng Li, Yanhui Liu, Eloi Pineda, Kaikai Song, Jichao Qiaodoi:10.1016/j.ijplas.2023.103873在金属玻璃中探测到的高能态雪崩动力学揭示了类似裂纹的剪切带机制When a sufficiently high stress is applied to a metallic glass, causing plastic deformation, the material undergoes structural reconfiguration through dissipative slip avalanche events that release local stresses. By utilizing isothermal annealing and cold rolling techniques to tune the energy levels of metallic glasses, it has been observed that structural rejuvenation is accompanied by structural relaxation, as evidenced by distinct changes in avalanche dynamics. We present detailed statistics of the avalanche dynamics during shear band formation in energy-tuned metallic glasses, ranging from structurally relaxed to rejuvenated states. By analyzing shear band characteristics and examining scaling exponents, avalanche durations, and stress relaxation rates, we can establish a connection between the local activation of shear transformation zones and the formation of macroscopic shear bands. The statistics of avalanche duration indicate that an increase in soft zones within metallic glasses can alleviate stress release and stabilize plastic flow, as evidenced by the characteristics of shear bands. We attribute the significant transition of serrated flow, observed at different energy levels (i.e., as-cast, relaxed, and rejuvenated states) to the variations in nucleation and multiplication of shear bands that originate from local weak spots. Analysis of the distinct avalanche dynamics suggests that in lower energy level metallic glasses, the nucleation and propagation of shear bands exhibit localized crack-like behavior, while in higher energy level metallic glasses, they display diffused crack-like characteristics. Indeed, our results strongly support that the decreased avalanches observed in the high energy level metallic glasses originate from the nucleation of numerous small shear bands, which directly compete with the propagation of the main local shear band. These findings deepen our fundamental understanding of the relationship between the microscopic mechanism of slip avalanche dynamics and shear banding, providing a pathway to control the plasticity of metallic glasses.当对金属玻璃施加足够大的应力导致塑性变形时，材料会通过释放局部应力的耗散滑移雪崩事件进行结构重构。通过利用等温退火和冷轧技术调节金属玻璃的能级，我们观察到结构年轻化伴随着结构松弛，雪崩动力学的明显变化就是证明。我们介绍了能量调谐金属玻璃剪切带形成过程中雪崩动力学的详细统计数据，包括从结构松弛状态到年轻化状态。通过分析剪切带特征并研究缩放指数、雪崩持续时间和应力松弛率，我们可以建立剪切转换区局部激活与宏观剪切带形成之间的联系。雪崩持续时间的统计结果表明，金属玻璃内部软区的增加可以缓解应力释放并稳定塑性流动，剪切带的特征也证明了这一点。我们认为，在不同能级（即铸造态、松弛态和恢复态）下观察到的锯齿流的显著转变是由于局部薄弱点产生的剪切带的成核和增殖变化造成的。对不同雪崩动力学的分析表明，在低能级金属玻璃中，剪切带的成核和传播表现出局部裂纹状行为，而在高能级金属玻璃中，则表现出扩散裂纹状特征。事实上，我们的研究结果有力地证明，在高能级金属玻璃中观察到的雪崩现象的减少源于无数小剪切带的成核，这些剪切带与主要局部剪切带的传播直接竞争。这些发现加深了我们对滑动雪崩动力学微观机制与剪切带之间关系的基本理解，为控制金属玻璃的塑性提供了一条途径。Thin-Walled StructuresWave propagation in beams with functionally graded porosity distribution under highly transient axial and transverse impactsM. Heshmati, S.K. Jalali, N.M. Pugnodoi:10.1016/j.tws.2023.111548在高瞬态轴向和横向冲击下，具有功能分级孔隙分布的梁中的波传播Recent advances in the manufacturing process provide a possibility of fabricating a new generation of porous materials denoted by functionally graded porous materials (FGPM). This paper aims to present a time domain analysis of wave propagation through the porous structures with functionally graded porosity distribution, which has not been completely studied before. For this purpose, the beams with different functionally graded porosity distributions subjected to both axial and transverse tip impact loads with a high-frequency content are investigated. The shear deformable cantilevered functionally graded porous beams with various porosity distributions through the beam thickness are studied. The governing differential equations are derived using the Hamiltonian principle based on the Timoshenko beam theory. A locking-free first-order shear deformable beam element is used to derive the finite element formulation of the equations. The Newmark time integration method is used to perform a time domain analysis of the equations of motion and to investigate the transient response of the beams. The axial and transverse wave propagation characteristics through functionally graded (FG) porous beams are found using time domain analysis of the results. Deflection and velocity time histories of the tip and each point of the beam, reflection time, and variation of support reactions are obtained. The influences of the porosity magnitude and porosity distribution on the wave propagation characteristics and overall time responses are investigated. The results reveal that porosity distribution has a significant effect on the wave amplitude, wave speed, and reflection from the boundary. Also, this study can help in a better understanding of porous structures' behavior subjected to high-transient impact loads in different engineering applications.制造工艺的最新进展为制造新一代多孔材料提供了可能，这种材料被称为功能分级多孔材料（FGPM）。本文旨在对波在具有功能分级孔隙率分布的多孔结构中的传播进行时域分析，而这在以前还没有过完整的研究。为此，本文研究了具有不同功能分级孔隙率分布的横梁，这些横梁同时承受轴向和横向尖端高频冲击载荷。研究了在梁厚度上具有不同孔隙率分布的可剪切变形悬臂功能分级多孔梁。基于季莫申科梁理论，利用哈密顿原理推导出了控制微分方程。无锁定一阶剪切变形梁元素用于推导方程的有限元公式。采用纽马克时间积分法对运动方程进行时域分析，并研究梁的瞬态响应。通过对结果进行时域分析，发现了穿过功能分级（FG）多孔梁的轴向和横向波传播特性。得出了梁顶端和各点的挠度和速度时间历程、反射时间以及支撑反作用力的变化。研究了孔隙率大小和孔隙率分布对波传播特性和整体时间响应的影响。结果表明，孔隙率分布对波幅、波速和边界反射有显著影响。此外，这项研究还有助于更好地理解多孔结构在不同工程应用中承受高瞬态冲击载荷时的行为。来源：复合材料力学仿真Composites FEM

【新文速递】2023年12月31日复合材料SCI期刊最新文章

Composite Structures

Composites Part B: Engineering

Composites Science and Technology

【新文速递】2024年1月1日固体力学SCI期刊最新文章