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课题组刘瑶副教授一篇稀土功能金属间化合物强韧化的论文被ACTA MATERIALIA录用
发布者: 马天宇 | 2024-05-29 | 2040

    2024年5月28日,课题组青年教师刘瑶副教授一篇论文“Isotropic negative thermal expansion in the multiple-phase La-Fe-Co-Si-Cu alloys with enhanced strength and ductility”被金属材料领域顶级刊物ACTA MATERIALIA录用!这也是她自2022年晋升副教授以来的第4篇ACTA MATERIALIA论文。祝贺她!

     

    该工作通过引入半共格第二相实现了脆性稀土功能金属间化合物的增强增韧,同时通过改变第二相体积分数实现了材料从负热膨胀到零膨胀和正热膨胀的连续可调。可简单理解为:把脆性的稀土功能金属间化合物改造成了强韧的“变形金刚”!

 

Abstract:

     

The negative thermal expansion materials based on the magneto-volume transition are usually poor in mechanical properties, severely inhibiting their application. Here in this article, we present the enforcement of the compressive strength and ductility of La(Fe,Co,Si)13 by directly adding extra Cu element and forming natural multiple phases alloys. Our study demonstrates that the extra Cu will facilitate the formation of LaCu2 phase that is semi-coherent with the La(Fe,Co,Si)13 phase, and the LaCuSi phase that exhibits a high density of stacking faults, which facilitates the enforcement of the strength and ductility of the alloy. Consequently, the natural alloys present increased strength from 70 MPa to 645 MPa, and the deformation behavior transforms from brittle to plastic, the ductility is simultaneously increased from 0.5% to 4.4%. The introduced phases exhibit positive thermal expansion behavior and compensate for the negative thermal expansion of the La(Fe,Co,Si)13 phase, and a tunable isotropic negative to zero thermal expansion is achieved in the alloys. Moreover, the alloys have high mechanical and negative thermal expansion performance reliability after 10000 times thermal cycles. This work denotes that Cu is a functional element to enforce the mechanical properties of the La(Fe,Co,Si)13 alloys, and also promotes a new possibility for obtaining low-cost and isotropic negative/zero thermal expansion materials with high application reliability.