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microscope observations, and strength calculations. The results reveal that a large number of deformation twins are formed in the 20% cold-worked steels with various silicon additions. The volume fraction of deformation twins and the density of dislocations increase with silicon content,while the twin thickness slightly decreases. A better strength–ductility combination is achieved by silicon......
="ChDivSummary">Effect of {10-12} twins on the mechanical properties of magnesium alloy has received considerable research interest. A hot-rolled AZ31 Mg alloy sheet was subjected to dynamic plastic... of twin region of the twin lamellar structured sample, indicating that the plasticity improvement caused by twins depends on the special strain path. The fracture morphology of the twin lamellar structured......
) was higher than that of weld metal(WM). In HAZ and BM, strain mainly loc alised at grain boundaries with large misorientation and there were lots of coincidence site lattice(CSL)∑3 boundaries related to twins inside grains, which led to the much higher fracture toughness of BM and HAZ than WM. The high numbers of twins as well as the less serious strain localization at grain boundaries resulted in the most......
was observed by use of optical microscope and transmission electron microscope, and the twin fraction was obtained as well. The results show that twins appear mainly at the stage of strain hardening and twin fraction increases with increase of the plastic deformation. The size of twins at early stage of plastic deformation is larger than that at latter stage, however, larger twins will break under large......
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wafer and mono-Si wafer. Intra-granular defects such as stacking faults, twins and microstructure defects were investigated on thin films by scan electron microscopy (SEM) technique. Key words:poly-Si......
Fe-Mn-Si-Al钢力学性能与显微结构研究张继明1,孙卫华1,孙浩1(1.山东省济南市济钢集团有限公司)摘 要:对3种成分Fe-Mn-Si-Al钢的力学性能,显微结构和重位晶界进行了研究,结果表明:随着钢中Mn,Si和Al元素含量的降低,材料的屈服强度和抗拉强度逐渐升高,伸长率逐渐降低,低∑值重位晶界出现频率依次为83.4%,36%和21%,并且钢中形变孪晶的数量逐渐减少.Fe-30Mn-3Si-3Al钢中形变孪晶分为一次孪晶和二次孪晶,一次孪晶和二次孪晶生长方向成60°夹角,大部分二次孪晶分布在一次孪晶的......
on the extension twins decrease from 5.39% to 2.22%. Whereas, the amount of the compression twins increases from 0.141% to 0.222%. Under condition of the stress concentration caused by lots of extension twins...的含量增多.挤压型材存在大量拉伸孪晶,且拉伸孪晶使得应力集中,达到非基面滑移的临界剪切应力,使非基面滑移启动,协调了晶粒c轴的应变,提高了型材的塑性变形能力. 表2 拉伸孪晶和压缩孪晶在晶界的分布 Table 2 Distribution of extension twins and compression twins at boundary 图7......
093 K, annealing twins appear in the alloy, and the number of twins increases with increasing holding time. Since the electric field can provide the enough energy for the movement of vacancies and atom, it is considered that the nucleus of the twins formed with formation stack faults due to the mismatch of local atom in crystal caused by the vacancies, and the twins will grow with the increase......
deformation, the scanning electron microscopy (SEM) and electron back-scattered diffraction technique (EBSD) were fully used. It is found that many tension twins (near 21%, volume fraction), a few compression twins and - secondary twins are generated during tension-compression cyclic deformation. The volume fractions of twins in samples 1, 2 and 3 are 8%, 21% and 4%, respectively......