The influence of crystallographic orientation on the void growth in FCC crystals was numerically simulated with 3D crystal plasticity finite element by using a 3D unit cell including a spherical void, and the rate-dep...The influence of crystallographic orientation on the void growth in FCC crystals was numerically simulated with 3D crystal plasticity finite element by using a 3D unit cell including a spherical void, and the rate-dependent crystal plasticity theory was implemented as a user material subroutine. The results of the simulations show that crystallographic orientation has significant influence on the growth behavior of the void. Different active slip systems of the regions around the void cause the discontinuity in lattice rotation around the void, and the corner-like region is formed. In the case of the void located at grain boundary, large heterogeneous deformation occurs between the two grains, and the equivalent plastic deformation along grain boundary near the void in the case of θ=45^o （θ is the angle between grain boundary direction and X-axis） is larger than the others. Large difference of orientation factor of the two grains leads to large equivalent plastic deformation along grain boundary, and the unit cell is more likely to fail by intergranular fracture.展开更多
This work focuses on numerical modeling of hydrostatic stress, which is critical to the formation of stress-induced voiding （SIV） in copper damascene interconnects. Using three-dimensional finite element analysis, t...This work focuses on numerical modeling of hydrostatic stress, which is critical to the formation of stress-induced voiding （SIV） in copper damascene interconnects. Using three-dimensional finite element analysis, the distribution of hydrostatic stress is examined in copper interconnects and models are based on the samples, which are fabricated in industry. In addition, hydrostatic stress is studied through the influences of different low-k dielectrics, barrier layers and line widths of copper lines, and the results indicate that hydrostatic stress is strongly dependent on these factors. Hydrostatic stress is highly non-uniform throughout the copper structure and the highest tensile hydrostatic stress exists on the top interface of all the copper lines.展开更多
在高温状态下,镍基单晶超合金的变形、损伤及断裂分析中,孔洞的长大都起着主要的作用。本研究进行了系列的蠕变、疲劳及热机械疲劳(TMF)试验。对试件的断面进行的 SEM 观察表明,所有的断面都是有许多小断面构成,在断面的中心,至少有一...在高温状态下,镍基单晶超合金的变形、损伤及断裂分析中,孔洞的长大都起着主要的作用。本研究进行了系列的蠕变、疲劳及热机械疲劳(TMF)试验。对试件的断面进行的 SEM 观察表明,所有的断面都是有许多小断面构成,在断面的中心,至少有一个孔洞。孔洞的尺寸与加载的条件相关。使用晶体塑性有限元程序对单胞模型进行分析,模拟孔洞的长大规律。给出了蠕变和弹塑性两种条件下的模拟结果及不同的晶体取向对孔穴长大的影响结果。对孔洞长大的有限元分析有助于对实验结果的理解。展开更多
基金Project(2005CB623706) supported by the Major State Basic Research Development Program of China
文摘The influence of crystallographic orientation on the void growth in FCC crystals was numerically simulated with 3D crystal plasticity finite element by using a 3D unit cell including a spherical void, and the rate-dependent crystal plasticity theory was implemented as a user material subroutine. The results of the simulations show that crystallographic orientation has significant influence on the growth behavior of the void. Different active slip systems of the regions around the void cause the discontinuity in lattice rotation around the void, and the corner-like region is formed. In the case of the void located at grain boundary, large heterogeneous deformation occurs between the two grains, and the equivalent plastic deformation along grain boundary near the void in the case of θ=45^o （θ is the angle between grain boundary direction and X-axis） is larger than the others. Large difference of orientation factor of the two grains leads to large equivalent plastic deformation along grain boundary, and the unit cell is more likely to fail by intergranular fracture.
基金Proiect supported by the National Natural Science Foundation of China(No.50871016).
文摘This work focuses on numerical modeling of hydrostatic stress, which is critical to the formation of stress-induced voiding （SIV） in copper damascene interconnects. Using three-dimensional finite element analysis, the distribution of hydrostatic stress is examined in copper interconnects and models are based on the samples, which are fabricated in industry. In addition, hydrostatic stress is studied through the influences of different low-k dielectrics, barrier layers and line widths of copper lines, and the results indicate that hydrostatic stress is strongly dependent on these factors. Hydrostatic stress is highly non-uniform throughout the copper structure and the highest tensile hydrostatic stress exists on the top interface of all the copper lines.
基金Natural Science Foundation of China (50005016, 50375124), Natural Science Foundation of Shaanxi Province and China aviation foundation (00B53010, 03B53003) as well as the Yangtze River foundation.
文摘在高温状态下,镍基单晶超合金的变形、损伤及断裂分析中,孔洞的长大都起着主要的作用。本研究进行了系列的蠕变、疲劳及热机械疲劳(TMF)试验。对试件的断面进行的 SEM 观察表明,所有的断面都是有许多小断面构成,在断面的中心,至少有一个孔洞。孔洞的尺寸与加载的条件相关。使用晶体塑性有限元程序对单胞模型进行分析,模拟孔洞的长大规律。给出了蠕变和弹塑性两种条件下的模拟结果及不同的晶体取向对孔穴长大的影响结果。对孔洞长大的有限元分析有助于对实验结果的理解。
