Phase transformations in Al-Ti-Mg powders consolidated by high-pressure torsion: Experiments and first-principles calculations
Phase transformations in Al-Ti-Mg powders consolidated by high-pressure torsion: Experiments and first-principles calculations
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高压扭转固结的 Al-Ti-Mg 粉末中的相变：实验和第一性原理计算
DOI：
10.1016/j.jallcom.2021.161815
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发表时间：
2021
影响因子：
6.2
通讯作者：
Horita Zenji
中科院分区：
文献类型：
--
作者：
Tang Yongpeng;Murayama Mitsuhiro;Edalati Kaveh;Wang Qing;Iikubo Satoshi;Masuda Takahiro;Higo Yuji;Tange Yoshinori;Ohishi Yasuo;Mito Masaki;Horita Zenji
在室温下，采用高压扭转（HPT），在6 GPa的压力下对Al-Ti-Mg等原子分数的粉末混合物进行了剧烈的塑性变形，使其完全固结。采用x射线衍射（XRD）和高分辨率透射电镜分析了拉伸和退火过程中微观组织的演变。XRD分析表明，固结试样中Ti含量较高，HPT加工过程中发生α相向ω相转变，ω相的总分数随着应变的增加而增加。通过100转HPT处理，晶粒细化至~100 nm，并形成纳米晶Al3Ti、alti3和TiAl等金属间化合物。随着应变的增加，硬度逐渐增加，在573 K下退火1.5 h，硬度进一步增加，尽管较硬的ω相反向转变为较软的α相，晶粒粗化到~450 nm，但由于al12mg17相的形成，硬度进一步提高。第一性原理计算表明，在HPT加工过程中，Al和Mg元素溶解在ω - Ti中。
A powder mixture of Al-Ti-Mg with an equal atomic fraction was subjected to severe plastic deformation using high-pressure torsion (HPT) under 6 GPa at room temperature for full consolidation. Microstructural evolution with respect to straining and annealing was examined by X-ray diffraction (XRD) analysis and high-resolution transmission electron microscopy. The XRD analysis revealed that Ti prevails in the consolidated sample and a phase transformation occurs from α phase to ω phase during HPT processing while the total fraction of the ω phase increases with straining. Grain refinement to ~100 nm was achieved through the HPT processing for 100 revolutions as well as the formation of nanograined intermetallics such as Al3Ti, AlTi3and TiAl. The hardness gradually increases with straining, and further increases by annealing at 573 K for 1.5 h due to the formation of an Al12Mg17phase despite the fact that the harder ω phase was reversely-transformed to the softer α phase and grains were coarsened to ~450 nm. First-principles calculations show that Al and Mg elements are dissolved into the ω − Ti during HPT processing.