ABSTRACT

We employ molecular dynamics simulations to investigate the evolution dynamics of $\left\{10\overline{1}2\right\}$ twinning in single-crystal Ti under shock loading. The shock compression applied perpendicular to the c-axis leads to the activation of $\left\{10\overline{1}2\right\}$ twins in single-crystal Ti. We find the twin variant activation for each case of the applied loading conditions follows Schmid criterion. However, the time for the activation of twin variants is not the same even with equal Schmid factor. The evolution and dominance of twin variants in each case of the applied loading conditions do not depend on the Schmid factor. High nucleation events and low overall twin volume fraction occur for the case where two conjugate pairs of twin variants activate while low nucleation events and high overall twin volume fraction occur for the case where only one conjugate pair of twin variants activate. Twin nucleation takes place throughout the simulation time for each case of the applied loading conditions. High twin growth occurs for the case where only one conjugate pair of twin variants activate in comparison to the case where two conjugate pairs of twin variants activate. This indicates that the number of activated twin variants affects the growth rate of the twins.

抽象的

我们采用分子动力学模拟研究分子的演化动力学。 $\left\{10\overline{\mathrm{1个}}\mathrm{2个}\right\}$在冲击载荷下孪晶成单晶Ti。垂直于c轴施加的冲击压缩导致激活$\left\{10\overline{\mathrm{1个}}\mathrm{2个}\right\}$双晶钛单晶。我们发现，在每种情况下，遵循Schmid准则对孪生变量的激活都适用。但是，即使具有相同的施密特因子，激活双变异体的时间也不相同。在所施加的负载条件的每种情况下，孪生变体的进化和优势都不取决于施密特因子。对于双变体的两个共轭对激活的情况，发生高成核事件，而双胞胎的总体积分数低，而对于双变体的一个共轭对激活，则发生低的成核事件和整体的孪生子体积分数高。在每种加载条件下，整个仿真过程中都会发生孪晶形核。与只有两个共轭对的孪生变体激活的情况相比，只有一对共轭对的孪生变体激活的情况下发生高孪生生长。这表明激活的双胞胎变异体的数量会影响双胞胎的生长速度。