The mechanical response of hexagonal close-packed metals is mediated by the formation of three-dimensional twin domain networks. To assess the morphology of these networks and statistically characterize their fingerprint, a three-dimensional twin network in cryogenically compressed high-purity Ti was reconstructed using serial sectioning electron backscatter diffraction (EBSD). Adjoining intergranular twin pairs, high order twin intersections (e.g. triple junctions of twins), and twin network hubs with over 15 separate intergranular and intragranular contacts are found to be salient morphological features of these networks. Using kinematics, the interfacial incompatibilities arising from these twin contact at grain boundaries are studied. The analysis reveals that numerous misaligned paired twin configurations generate high incompatibilities, likely resulting from the contact between two initially distinct twin chains. These configurations generally induce higher incompatibilities than the ones of the individual twins, equivalent to introducing a dense wall of dislocations at twin-grain boundary facets with a dislocation spacing on the order of 1.3 nm or less. In contrast, the shear incompatibilities resulting from the formation of aligned twin pairs are generally reduced compared to non-transmitting twins. Further, twin triple junctions and branches – consisting of intergranular contact of three co-located twins – induce higher incompatibilities on average compared to adjoining twin pairs and represent sources of high shear localization in the domain network.

中文翻译：

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六边形密排金属中的孪生网络：形态、连通性和不相容性


六方密排金属的机械响应是由三维双域网络的形成介导的。为了评估这些网络的形态并统计表征它们的指纹，使用连续切片电子背散射衍射 （EBSD） 重建了低温压缩高纯度 Ti 中的三维孪生网络。相邻的晶间孪生对、高阶孪生交集（例如孪生的三重交界处）和具有超过 15 个单独的晶间和晶内接触的孪生网络枢纽是这些网络的显着形态特征。使用运动学，研究了晶界处这些孪生接触引起的界面不相容性。分析表明，许多未对准的成对孪生构型会产生高度不相容性，这可能是由于两条最初不同的双链之间的接触造成的。这些构型通常比单个孪晶的不相容性更高，相当于在双晶界面上引入致密的位错壁，位错间距约为 1.3 nm 或更小。相比之下，与非透射孪晶相比，由对齐孪晶对形成引起的剪切不相容性通常较低。此外，与相邻的孪生对相比，孪生结和分支（由三个共置孪生孪生的晶间接触组成）平均会引起更高的不兼容性，并代表域网络中高剪切定位的来源。