Wu Qingfeng, He Feng, Li Junjie, Kim Hyoung Seop, Wang Zhijun, Wang Jincheng
State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an, 710072, China.
Graduate Institute of Ferrous & Energy Materials Technology, Pohang University of Science and Technology (POSTECH), Pohang, 37673, South Korea.
Nat Commun. 2022 Aug 10;13(1):4697. doi: 10.1038/s41467-022-32444-4.
Excellent ductility is crucial not only for shaping but also for strengthening metals and alloys. The ever most widely used eutectic alloys are suffering from the limited ductility and losing competitiveness among advanced structural materials. Here we report a distinctive concept of phase-selective recrystallization to overcome this challenge for eutectic alloys by triggering the strain hardening capacity of the duplex phases completely. We manipulate the strain partitioning behavior of the two phases in a eutectic high-entropy alloy (EHEA) to obtain the phase-selectively recrystallized microstructure with a fully recrystallized soft phase embedded in the skeleton of a hard phase. The resulting microstructure fully releases the strain hardening capacity in EHEA by eliminating the weak boundaries. Our phase-selectively recrystallized EHEA achieves a high ductility of ∼35% uniform elongation with true stress of ∼2 GPa. This concept is universal for various duplex alloys with soft and hard phases and opens new frontiers for traditional eutectic alloys as high-strength metallic materials.
优异的延展性不仅对金属和合金的成型至关重要，对其强化也很关键。一直以来使用最广泛的共晶合金正面临着延展性有限的问题，并且在先进结构材料中逐渐失去竞争力。在此，我们报告一种独特的相选择性再结晶概念，通过完全激发双相的应变硬化能力来克服共晶合金面临的这一挑战。我们操控共晶高熵合金（EHEA）中两相的应变分配行为，以获得相选择性再结晶微观结构，其中完全再结晶的软相嵌入硬相的骨架中。所得微观结构通过消除弱界面，充分释放了EHEA中的应变硬化能力。我们的相选择性再结晶EHEA实现了约35%的均匀伸长率和约2 GPa的真实应力下的高延展性。这一概念对各种软硬双相合金具有普遍性，并为传统共晶合金作为高强度金属材料开辟了新的前沿领域。
