Decoupling between Shockley partials and stacking faults strengthens multiprincipal element alloys
Decoupling between Shockley partials and stacking faults strengthens multiprincipal element alloys
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DOI：
10.1073/pnas.2114167118
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发表时间：
2021-12
期刊：
影响因子：
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通讯作者：
Zongrui Pei;Siyuan Zhang;Yinkai Lei;Fan Zhang;Mingwei Chen
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文献类型：
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作者：
Zongrui Pei;Siyuan Zhang;Yinkai Lei;Fan Zhang;Mingwei Chen
合金在人类文明史上起着至关重要的作用。近年来，出现了一组不含主元素的新型合金。多主元素合金因其优异的力学性能而受到广泛的研究。虽然我们知道许多多主元素合金具有高屈服应力，但其潜在的机制起源仍然难以捉摸。借助于最先进的理论和实验方法，我们证明了优异的力学性能有不同的起源。在这些合金中，通过肖克利部分和层错的强化效应可以在不同的方向上发生变化，打破了传统的认识。这些见解概括了多主元素合金中共存的强化机制的物理图景，并为设计高性能合金提供了途径。力学性能是结构材料的基础，其中位错在描述其力学行为方面起着决定性的作用。近十年来，多主元素合金的高屈服应力受到了广泛的关注，但其力学根源之间的关系仍是一个谜。我们对密度泛函理论、原子模拟和高分辨率显微镜的多尺度研究表明，mpea的优异力学性能有不同的起源。在mpea中，通过肖克利部分和层错的强化效应可以解耦，打破了低层错能与宽部分位错耦合的传统观念。本研究阐明了强化效应的机理根源，为材料设计的物理预测模型奠定了基础。
Significance Alloys play crucial roles in the civilization history of human beings. Recently, a group of novel alloys without principal elements—i.e., multiprincipal element alloys—have been extensively studied due to their excellent mechanical performance. Although we know many multiprincipal element alloys have high-yield stresses, the underlying mechanistic origins remain elusive. Assisted by state-of-the-art theoretical and experimental methods, we show that the excellent mechanical properties have diverse origins. The strengthening effects through Shockley partials and stacking faults can change in different directions in these alloys, breaking the conventional wisdom. These insights generalize the physical picture for the strengthening mechanisms that can coexist in the multiprincipal element alloys and provide a pathway to design high-performance alloys. Mechanical properties are fundamental to structural materials, where dislocations play a decisive role in describing their mechanical behavior. Although the high-yield stresses of multiprincipal element alloys (MPEAs) have received extensive attention in the last decade, the relation between their mechanistic origins remains elusive. Our multiscale study of density functional theory, atomistic simulations, and high-resolution microscopy shows that the excellent mechanical properties of MPEAs have diverse origins. The strengthening effects through Shockley partials and stacking faults can be decoupled in MPEAs, breaking the conventional wisdom that low stacking fault energies are coupled with wide partial dislocations. This study clarifies the mechanistic origins for the strengthening effects, laying the foundation for physics-informed predictive models for materials design.