体心立方多晶膜中应变能密度的各向异性分析

Anisotropy analysis of strain-energy density in bcc-polycrystalline films

根据弹性理论和多晶膜的屈服强度公式 ,计算了附着在基体上体心立方多晶薄膜中不同取向晶粒中的应变能密度 .结果表明 :1)在屈服之前 ,对Fe和Ta两种薄膜 ,4个最小的应变能密度对应的晶粒取向依次为 (10 0 ) ,(5 10 ) ,(4 10 )和 (5 11) ;对Cr,Mo ,Nb和V四种薄膜 ,4个最小的应变能密度对应的晶粒取向依次为 (111) ,(332 ) ,(32 2 )和(2 2 1) ;对W膜 ,应变能密度与晶粒取向无关 .2 )在屈服的体心立方多晶膜中 ,4个最小的应变能密度对应的晶粒取向依次为 (10 0 ) ,(111) ,(110 )和 (4 11) .从应变能的最小化考虑 ,这些取向的晶粒将依次优先生长 .

Based on elastic theory and yield strength formula of polycrystalline films, the strain-energy densities in differently oriented grains have been calculated for a bcc-polycrystalline film on a substrate. The results show that, (1) prior to yielding, the Fe and Ta are basically similar and with (100), (510), (410) and (511) oriented grains having the lowest strain-energy densities. For Cr, Mo, Nb and V, however, the four lowest strain-energy densities correspond to the grains with (111), (332), (322) and (211) planes oriented parallel to the film surface. For isotropic W, the strain energy density is independent of the grain orientation. (2) In all of yielded bcc-polycrystalline films, the four lowest strain energy densities correspond to the grains with (100), (111), (110) and (411) planes oriented parallel to the film surface. Considering strain energy minimization, we predicate that the grains with these orientations should be favorable in crystal growth successively.