当前位置: X-MOL 学术Nature › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Enhanced strength and ductility in a high-entropy alloy via ordered oxygen complexes
Nature ( IF 64.8 ) Pub Date : 2018-11-01 , DOI: 10.1038/s41586-018-0685-y
Zhifeng Lei , Xiongjun Liu , Yuan Wu , Hui Wang , Suihe Jiang , Shudao Wang , Xidong Hui , Yidong Wu , Baptiste Gault , Paraskevas Kontis , Dierk Raabe , Lin Gu , Qinghua Zhang , Houwen Chen , Hongtao Wang , Jiabin Liu , Ke An , Qiaoshi Zeng , Tai-Gang Nieh , Zhaoping Lu

Oxygen, one of the most abundant elements on Earth, often forms an undesired interstitial impurity or ceramic phase (such as an oxide particle) in metallic materials. Even when it adds strength, oxygen doping renders metals brittle1–3. Here we show that oxygen can take the form of ordered oxygen complexes, a state in between oxide particles and frequently occurring random interstitials. Unlike traditional interstitial strengthening4,5, such ordered interstitial complexes lead to unprecedented enhancement in both strength and ductility in compositionally complex solid solutions, the so-called high-entropy alloys (HEAs)6–10. The tensile strength is enhanced (by 48.5 ± 1.8 per cent) and ductility is substantially improved (by 95.2 ± 8.1 per cent) when doping a model TiZrHfNb HEA with 2.0 atomic per cent oxygen, thus breaking the long-standing strength–ductility trade-off11. The oxygen complexes are ordered nanoscale regions within the HEA characterized by (O, Zr, Ti)-rich atomic complexes whose formation is promoted by the existence of chemical short-range ordering among some of the substitutional matrix elements in the HEAs. Carbon has been reported to improve strength and ductility simultaneously in face-centred cubic HEAs12, by lowering the stacking fault energy and increasing the lattice friction stress. By contrast, the ordered interstitial complexes described here change the dislocation shear mode from planar slip to wavy slip, and promote double cross-slip and thus dislocation multiplication through the formation of Frank–Read sources (a mechanism explaining the generation of multiple dislocations) during deformation. This ordered interstitial complex-mediated strain-hardening mechanism should be particularly useful in Ti-, Zr- and Hf-containing alloys, in which interstitial elements are highly undesirable owing to their embrittlement effects, and in alloys where tuning the stacking fault energy and exploiting athermal transformations13 do not lead to property enhancement. These results provide insight into the role of interstitial solid solutions and associated ordering strengthening mechanisms in metallic materials.Ordered oxygen complexes in high-entropy alloys enhance both strength and ductility in these compositionally complex solid solutions.

中文翻译:

通过有序氧配合物提高高熵合金的强度和延展性

氧是地球上最丰富的元素之一,通常会在金属材料中形成不需要的间隙杂质或陶瓷相(例如氧化物颗粒)。即使增加了强度,氧掺杂也会使金属变脆1-3。在这里,我们表明氧可以采取有序氧复合物的形式,一种介于氧化物颗粒和经常出现的随机间隙之间的状态。与传统的填隙强化 4,5 不同,这种有序填隙复合物在成分复杂的固溶体(即所谓的高熵合金 (HEAs)6-10)中导致强度和延展性的前所未有的增强。当用 2.0 原子百分比的氧掺杂模型 TiZrHfNb HEA 时,拉伸强度增强(48.5 ± 1.8%),延展性显着提高(95.2 ± 8.1%),从而打破了长期存在的强度-延展性权衡11。氧配合物是 HEA 内有序的纳米级区域,其特征是富含 (O、Zr、Ti) 的原子配合物,其形成是由于 HEA 中一些替代基质元素之间存在化学短程排序。据报道,碳通过降低堆垛层错能和增加晶格摩擦应力,同时提高面心立方 HEAs 的强度和延展性。相比之下,这里描述的有序间隙复合物将位错剪切模式从平面滑移改变为波浪滑移,并通过弗兰克-雷德源(一种解释多重位错产生的机制)的形成促进双交叉滑移,从而促进位错增殖。形变。这种有序的填隙复合物介导的应变硬化机制在含 Ti、Zr 和 Hf 的合金中特别有用,其中间隙元素由于其脆化效应而非常不受欢迎,以及在合金中调整堆垛层错能并利用无热转变 13 不会导致性能增强。这些结果提供了对间隙固溶体的作用和金属材料中相关有序强化机制的深入了解。高熵合金中的有序氧配合物增强了这些成分复杂的固溶体的强度和延展性。在合金中,调整堆垛层错能和利用非热转变 13 不会导致性能增强。这些结果提供了对间隙固溶体的作用和金属材料中相关有序强化机制的深入了解。高熵合金中的有序氧配合物增强了这些成分复杂的固溶体的强度和延展性。在合金中,调整堆垛层错能和利用非热转变 13 不会导致性能增强。这些结果提供了对间隙固溶体的作用和金属材料中相关有序强化机制的深入了解。高熵合金中的有序氧配合物增强了这些成分复杂的固溶体的强度和延展性。
更新日期:2018-11-01
down
wechat
bug