期刊
PHYSICAL REVIEW LETTERS
卷 115, 期 10, 页码 -出版社
AMER PHYSICAL SOC
DOI: 10.1103/PhysRevLett.115.105501
关键词
-
资金
- Defense Advanced Research Projects Agency [W31P4Q-13-1-0010]
- National Science Foundation [DMR-1436985]
- Army Research Laboratory [W911NF-12-2-0022]
- Division Of Materials Research
- Direct For Mathematical & Physical Scien [1436985] Funding Source: National Science Foundation
Ceramics are strong, but their low fracture toughness prevents extended engineering applications. In particular, boron carbide (B4C), the third hardest material in nature, has not been incorporated into many commercial applications because it exhibits anomalous failure when subjected to hypervelocity impact. To determine the atomistic origin of this brittle failure, we performed large-scale (similar to 200000 atoms/cell) reactive-molecular-dynamics simulations of shear deformations of B4C, using the quantum-mechanics-derived reactive force field simulation. We examined the (0001)/< 10 (1) over bar0 > slip system related to deformation twinning and the (01 (1) over bar(1) over bar)/<(1) over bar 101 > slip system related to amorphous band formation. We find that brittle failure in B4C arises from formation of higher density amorphous bands due to fracture of the icosahedra, a unique feature of these boron based materials. This leads to negative pressure and cavitation resulting in crack opening. Thus, to design ductile materials based on B4C we propose alloying aimed at promoting shear relaxation through intericosahedral slip that avoids icosahedral fracture.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据