Atomistic deformation modes and intrinsic brittleness of Al(4)SiC(4): A first-principles investigation

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	Atomistic deformation modes and intrinsic brittleness of Al(4)SiC(4): A first-principles investigation
	T. Liao; J. Y. Wang; Y. C. Zhou
	2006
发表期刊	Physical Review B
ISSN	1098-0121
卷号	74 期号:17
摘要	From crystallographic point of view, Al(4)SiC(4) can be described as Al(4)C(3)-type and hexagonal SiC-type structural units alternatively stacked along [0001] direction. However, relationship between this layered crystal structure and mechanical properties is not fully established for Al(4)SiC(4), except for the reported bulk modulus locating between those of Al(4)C(3) and SiC. Based on the first-principles pseudopotential total energy method, we calculated the elastic stiffness of Al(4)SiC(4), and reported on its ideal tensile and shear stress-strain relationships considering different structural deformation modes. Elastic properties of Al(4)SiC(4) are dominated by the Al(4)C(3)-type structural units and exhibit similar results with those of Al(4)C(3). Furthermore, the atomistic deformation modes of Al(4)SiC(4) upon tensile and shear deformations are illustrated and compared with Al(4)C(3) as well. Since the tension-induced bond breaking occurs inside the constitutive Al(4)C(3)-type unit, the ternary carbide has similar ideal tensile strength with Al(4)C(3). On the other hand, despite the softening of strong coupling between Al(4)C(3)- and SiC-type structural units is involved in shear, the shear strength for Al(4)SiC(4) is, however, lower than the tensile strength, since p-state involved Al-C bonds respond more readily to the shear deformation than to tension. In addition, based on the comparison of strain energies at the maximum stresses, i.e., ideal strengths, for both tension and shear, we suggest that structural failure occurs in tensile deformation firstly and, thus confirms an intrinsic brittleness of Al(4)SiC(4). For crystal structure arranged in alternatively stacking configuration, such as Al(4)SiC(4), mechanical properties can be traced back to the constituent units, and are also related to the coupling strengths between each constituent unit. The results might provide a computational method to predict ductile or brittle response of a solid to applied deformations.
部门归属	chinese acad sci, inst met res, shenyang natl lab mat sci, shenyang 110016, peoples r china. chinese acad sci, grad sch, beijing 100039, peoples r china. chinese acad sci, inst met res, int ctr mat phys, shenyang 110016, peoples r china.;liao, t (reprint author), chinese acad sci, inst met res, shenyang natl lab mat sci, shenyang 110016, peoples r china
关键词	Sintered Bodies Ab-initio Crystals Oxidation Aluminum Behavior Solids Phases Shear Cr
URL	查看原文
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/34325
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	T. Liao,J. Y. Wang,Y. C. Zhou. Atomistic deformation modes and intrinsic brittleness of Al(4)SiC(4): A first-principles investigation[J]. Physical Review B,2006,74(17).
APA	T. Liao,J. Y. Wang,&Y. C. Zhou.(2006).Atomistic deformation modes and intrinsic brittleness of Al(4)SiC(4): A first-principles investigation.Physical Review B,74(17).
MLA	T. Liao,et al."Atomistic deformation modes and intrinsic brittleness of Al(4)SiC(4): A first-principles investigation".Physical Review B 74.17(2006).