Department of Materials Science and Engineering &Institute of Materials Science, 97 North Eagleville Road, Unit 3136, Storrs, CT, 06269-3136, USA.
Sci Rep. 2017 Jan 9;7:40409. doi: 10.1038/srep40409.
Bulk metallic glasses (BMGs) and nanocrystalline metals (NMs) have been extensively investigated due to their superior strengths and elastic limits. Despite these excellent mechanical properties, low ductility at room temperature and poor microstructural stability at elevated temperatures often limit their practical applications. Thus, there is a need for a metallic material system that can overcome these performance limits of BMGs and NMs. Here, we present novel Cu-based metal-intermetallic nanostructured composites (MINCs), which exhibit high ultimate compressive strengths (over 2 GPa), high compressive failure strain (over 20%), and superior microstructural stability even at temperatures above the glass transition temperature of Cu-based BMGs. Rapid solidification produces a unique ultra-fine microstructure that contains a large volume fraction of CuZr superlattice intermetallic compound; this contributes to the high strength and superior thermal stability. Mechanical and microstructural characterizations reveal that substantial accumulation of phase boundary sliding at metal/intermetallic interfaces accounts for the extensive ductility observed.
大块非晶合金（BMGs）和纳米晶金属（NMs）因其优异的强度和弹性极限而得到了广泛的研究。尽管这些机械性能非常出色，但在室温下的低延展性和在高温下的差的微观结构稳定性通常限制了它们的实际应用。因此，需要有一种金属材料体系，可以克服 BMGs 和 NMs 的这些性能限制。在这里，我们提出了一种新型的基于 Cu 的金属-金属间化合物纳米结构复合材料（MINCs），它具有超高的抗压强度（超过 2 GPa）、高的压缩失效应变（超过 20%）和优异的微观结构稳定性，甚至在高于 Cu 基 BMG 玻璃化转变温度的温度下也是如此。快速凝固产生了一种独特的超细微观结构，其中包含大量的 CuZr 超晶格金属间化合物；这有助于提高强度和优异的热稳定性。力学和微观结构表征表明，金属/金属间化合物界面处的相界滑动大量积累是观察到的高延展性的原因。
