论文部分内容阅读
利用液压试验机对金属钛、镁和钴进行循环加载-卸载压缩试验,利用引伸计测量应变,获得样品的应力-应变曲线。钛、镁和钴因为六方密堆积晶体结构,具有塑性各向异性,导致一定的非线性弹性。这些非线性弹性在循环加载应力-应变曲线中表现为滞后环。研究表明,适当的预变形可以增大这些材料的非线性弹性。粗晶样品一般比细晶样品具有较大的非线性弹性。一种源于三元碳化物Ti3SiC2的初始弯折带(Incipient kink bands)理论可以解释这些材料的非线性弹性以及与非线性弹性相联系的微屈服、阻尼减震。一种经典滞后模型Preisach-Mayergoyz模型,可以用来计算这些材料的非线性变形量。
The cyclic loading-unloading compression tests of titanium, magnesium and cobalt were carried out by hydraulic testing machine, and the strain was measured by extensometer to obtain the stress-strain curve of the sample. Titanium, magnesium and cobalt have plastic anisotropy due to hexagonal close-packed crystal structure, resulting in a certain degree of nonlinear elasticity. These non-linear elasticities appear as hysteresis loops in cyclic loading stress-strain curves. Research shows that proper pre-deformation can increase the nonlinear elasticity of these materials. Coarse grain samples generally have greater nonlinear elasticity than fine grain samples. An Incipient kink bands theory derived from ternary carbide Ti3SiC2 can explain the nonlinear elasticity of these materials as well as the micro-yield and damping damping associated with nonlinear elasticity. A classic hysteresis model Preisach-Mayergoyz model can be used to calculate the nonlinear deformation of these materials.