面心立方晶体强度与塑性变形机制的尺寸效应

项目名称： 面心立方晶体强度与塑性变形机制的尺寸效应

项目编号： No.51471170

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 一般工业技术

项目作者： 张哲峰

作者单位： 中国科学院金属研究所

项目金额： 84万元

中文摘要： 选择不同晶体取向面心立方铝/镍/铜/银单晶体、含大角晶界和孪晶界的铜双晶体作为研究对象，制备直径或厚度为1-100微米的小尺寸样品，采用高精度平压头压痕仪、高精度微小载荷试验机和扫描（透射）电镜的原位载荷施加系统，对上述微小尺寸样品进行压缩或拉伸力学性能试验，研究具有不同晶体学取向和层错能的小尺寸单晶体、含大角晶界与孪晶界的铜双晶体的强度与塑性变形行为，结合扫描与透射电镜观察开动的滑移系及位错组态：1）揭示晶体取向和层错能对不同面心立方金属单晶体压缩/拉伸强度与塑性变形机制影响的尺寸效应；2）揭示大角晶界和孪晶界对铜双晶体压缩/拉伸强度与塑性变形机制的影响尺寸效应。结合晶体取向、层错能和晶界与孪晶界等内在因素进一步认识小尺寸单、双晶体塑性变形机制的物理本质，并利用强度理论分析上述不同晶体材料强度变化的尺寸效应，为提出或发展新的强化机制与强度理论提供实验证据和理论基础。

中文关键词： 晶体取向；层错能；晶界与孪晶界；强度；尺寸效应

英文摘要： In the project, typical FCC metals (Al, Ni, Cu and Ag) single crystals and bivrystals with large-angle grain boundaries or twin boundaries will be employed to machine the samples with size of 1-100 micrometer. Then, high-presion low-loading testing machine will be used to apply stress or strain to the samples above to in-situ investigate their deformation mechanisms and strength under scanning electron microscopy (SEM) or transmission electron microscopy (TEM). The effects of crystallographic orientation, stacking fault energy, grain boundary, twin boundary and sample size on the deformation and strength of the single crystals and bicrystals will be revealed with SEM or TEM. The main goals include: 1) to reveal the size effects of orientation and stacking fault energy on the tensile/compressive strength and deformation mechanisms of the single crystals pillars; 2) to reveal the size effects of the grain boundary or twin boudary on the tensile/compressive strength and deformation mechanisms of the bicrystals pillars. In combination with the crystallographic orientation, stacking fault energy, grain boundaries and twin boundaries, the physical nature of the palstic deformation mechanisms will be explored. In terms of the strength thoeries on the smaples with different size range above, the strengthening mechanisms and strength theory will be further developed for better understanding on the relation between materials nature and their mechanical properties.

英文关键词： Crystallographic orientation;Stacking fault energy;Grain boundary and twin boundary;Strength;Size effect