Fu Zhiqiang, Jiang Lin, Wardini Jenna L, MacDonald Benjamin E, Wen Haiming, Xiong Wei, Zhang Dalong, Zhou Yizhang, Rupert Timothy J, Chen Weiping, Lavernia Enrique J
Guangdong Key Laboratory for Advanced Metallic Materials Processing, South China University of Technology, Guangzhou, Guangdong 510640, China.
Department of Materials Science and Engineering, University of California, Irvine, CA 92697, USA.
Sci Adv. 2018 Oct 12;4(10):eaat8712. doi: 10.1126/sciadv.aat8712. eCollection 2018 Oct.
High-entropy alloys (HEAs) are a class of metallic materials that have revolutionized alloy design. They are known for their high compressive strengths, often greater than 1 GPa; however, the tensile strengths of most reported HEAs are limited. Here, we report a strategy for the design and fabrication of HEAs that can achieve ultrahigh tensile strengths. The proposed strategy involves the introduction of a high density of hierarchical intragranular nanoprecipitates. To establish the validity of this strategy, we designed and fabricated a bulk FeCoNiAlTi HEA to consist of a principal face-centered cubic (fcc) phase containing hierarchical intragranular nanoprecipitates. Our results show that precipitation strengthening, as one of the main strengthening mechanisms, contributes to a tensile yield strength (σ) of ~1.86 GPa and an ultimate tensile strength of ~2.52 GPa at room temperature, which heretofore represents the highest strength reported for an HEA with an appreciable failure strain of ~5.2%.
高熵合金（HEAs）是一类彻底变革了合金设计的金属材料。它们以其高抗压强度而闻名，通常大于1吉帕；然而，大多数已报道的高熵合金的抗拉强度有限。在此，我们报告一种能够实现超高抗拉强度的高熵合金设计与制造策略。所提出的策略涉及引入高密度的分级晶内纳米析出相。为了验证该策略的有效性，我们设计并制造了一种块状FeCoNiAlTi高熵合金，其由包含分级晶内纳米析出相的主要面心立方（fcc）相组成。我们的结果表明，作为主要强化机制之一的析出强化，在室温下有助于实现约1.86吉帕的抗拉屈服强度（σ）和约2.52吉帕的极限抗拉强度，这是迄今为止报道的具有约5.2%可观失效应变的高熵合金的最高强度。
