Dislocation structure of non-habit plane of α precipitates in a Ti–7.26 wt.% Cr alloy

Ye, Fan; Zhang, W.-Z.

doi:10.1016/j.actamat.2005.10.017

Cited by 18 publications

(19 citation statements)

References 14 publications

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“…The misfit varies in a modulated periodicity, and the two orders of misfit periodicity correspond respectively to the primary and secondary NCS clusters. Therefore, these double periodic NCS clusters are apparently associated with the two sets of dislocations observed from the edge facets [14].…”

Section: Periodicity Of Ncs Clusters and Their Association With Moirémentioning

confidence: 93%

“…This Burgers vector is consistent with the (0 1 1) b extra planes observed at the positions of the dislocations [5,7], but the proposed super ledges were not observed. Recently, an edge facet with a normal close to (À1 À1.4 3.2) b ($// (À2.4 3.4 À1 10.5) a ) was identified [14]. Two sets of dislocations were observed in this facet, and both of them were parallel to the dislocations in the habit plane.…”

Section: Introductionmentioning

confidence: 97%

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Near-coincidence-sites modeling of the edge facet dislocation structures of α precipitates in a Ti–7.26 wt.% Cr alloy

Zhang

Qiu

2006

Acta Materialia

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While much attention has been paid to the orientations and structures of the habit planes of various precipitates, the orientations and structures of the edge facets are less well understood. This work presents a new approach to the interpretation of edge facets. The orientations and dislocation structures of the edge facets of a precipitates in a b matrix in a Ti-7.26 wt.% Cr alloy were investigated with a near-coincidence-sites (NCS) model combined with the analysis of Moiré planes based on the O-lattice theory. The distribution of NCS clusters exhibits two orders of modulated periodicities, which can be defined by the approximate intersections between several sets of Moiré planes. Two possible edge facets are suggested, based on the NCS distribution. Based on the misfit analysis, the dislocation structures in the edge facets were calculated. The calculated orientations and dislocation structures of the edge facets are consistent with the experimental observations.

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Section: Periodicity Of Ncs Clusters and Their Association With Moirémentioning

confidence: 93%

Section: Introductionmentioning

confidence: 97%

Near-coincidence-sites modeling of the edge facet dislocation structures of α precipitates in a Ti–7.26 wt.% Cr alloy

Zhang

Qiu

2006

Acta Materialia

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“…Кроме того, на торцевой грани наблюдали дислокации несоответствия "a" [11,12] и "a + c"-типа [19]. [26].…”

Section: A) все эти плоскости содержат направле-ние [0001] α || [110]unclassified

“…На боковой поверхности (Side Face) сопряжения присутствуют два ряда дислокаций несоответствия "a"-типа, линии которых расположе-ны, как правило, в плотноупакованных плоскостях (0001) α || {110} β α-или β-фазы, а на торцевой поверх-ности (End Facet) пластин наблюдали два или три ряда дислокаций несоответствия "a", "c" или "a + c"-типа [19] (рис. 1b).…”

Section: Introductionunclassified

“…Строение торцевой β / α границы вызывает наиболь-шие дискуссии [11,12,19]. Вероятно, это связано с тем, что торцевая поверхность раздела может состоять из фа-сеток, образованных разными парами плоскостей.…”

Section: Introductionunclassified

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Effect of temperature on the specific energy of β / α interfaces in Ti-6Al-4V alloy

Murzinova¹

2017

LoM

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Most of titanium alloys contain two phases at temperatures of processing and exploitation: α-phase with HCP lattice and β-phase with BCC lattice. Stability of two-phase structure and thermodynamics of β / α transformation, which occurs in a wide range of temperatures, considerably depend on the specific energy of interphase boundaries, and, consequently, on their structure. Basing on the literature data, four schemes of "planar" semicoherent interfaces, in which mismatches in interatomic distances are accommodated by two or three sets of edge misfit dislocations, were plotted. Such types of conjugation are observed on side and end interfaces of lamellas in titanium alloys. The procedure developed by J. H. van der Merwe and G. J. Shiflet was used for estimation of specific energy of interphase boundaries in Ti-6Al-4V alloy. Effect of temperature and content of alloying elements on lattice parameters and elastic properties of the α-and β-phases in Ti-6Al-4V alloy was taken into account for calculations. This approach allowed one to estimate the change in the energy of interphase boundaries in the alloy in temperature interval 600 -975°C, where diffusion β / α transformation and enrichment of β-phase by vanadium are observed. It was shown that the energy of interphase boundaries in Ti-6Al-4V alloy decreased by 1.3 -1.5 times with increasing temperature from 600 to 975°C at all examined types of conjugation. Depending on the structure the energy of interphase boundaries can vary from 0.201 to 0.337 J / m 2 at 975°C and from 0.298 to 0.429 J / m 2 at 600°C. Во многих титановых сплавах при температурах обработки и эксплуатации присутствуют две фазы: α-фаза с ГПУ решеткой и β-фаза с ОЦК решеткой. Стабильность двухфазной структуры и термодинамика фазового β / α превра-щения, которое протекает в широком интервале температур, во многом зависят от удельной энергии межфазных границ, и, следовательно, их строения. На основе обобщения литературных данных об атомном и дислокационном строении границ между фазами с ОЦК и ГПУ решетками предложены четыре схемы строения «плоских» полукоге-рентных межфазных границ, на которых несоответствия межатомных расстояний компенсируются двумя или тремя рядами краевых дислокаций несоответствия. Границы сопряжения такого типа наблюдаются на боковых и торцевых гранях пластин в титановых сплавах. По методике, разработанной ван дер Мерве и Шифлитом, выполнена оценка удельной энергии межфазных границ разного типа в сплаве Ti-6Al-4V. Расчеты проводились с учетом литературных данных о влиянии содержания легирующих элементов и температуры на параметры решеток и упругие свойства фаз сплава Ti-6Al-4V. Это позволило оценить изменение энергии межфазных границ в сплаве Ti-6Al-4V в интер-вале температур 600 -975°С, при которых наблюдается развитие диффузионного β / α превращения и интенсивное обогащение β-фазы ванадием. Показано, что при всех вариантах сопряжения энергия межфазных границ в сплаве Ti-6Al-4V монотонно уменьшается в 1,3 -1,5 раза с повышением температуры от 600 до 975°С. При постоянной тем-пер...

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The Effect of β Stabilizers on the Structure and Energy of α/β Interfaces in Titanium Alloys

Murzinova

Zherebtsov

Клименко

et al. 2021

Metall Mater Trans A

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The structure and energy associated with interfaces between the BCC and HCP lattices (b and a phase, respectively) in titanium alloys with commonly used b stabilizers were analyzed. For this purpose, the crystallographic structure of the matching facets of broad, side and end faces was described using misfit dislocations and structural ledges which compensate the mismatch in atomic spacing of the a and b phases. The effect of the b/a transformation temperature due to various concentration of b stabilizers on periodicity of misfit dislocations and structural ledges was estimated. The van der Merwe approach was used to calculate energy of different matching facets. An increase in the percentage of b-stabilizing elements was found to result in a decrease in the lattice-parameter ratio (a b /a a ) and an increase in the energy of all faces. The dependence of the interface energy on the a b /a a ratio was for the first time quantified, and insight into the preferred shape of a-phase precipitates was obtained.

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Dislocation structure of non-habit plane of α precipitates in a Ti–7.26 wt.% Cr alloy

Cited by 18 publications

References 14 publications

Near-coincidence-sites modeling of the edge facet dislocation structures of α precipitates in a Ti–7.26 wt.% Cr alloy

Near-coincidence-sites modeling of the edge facet dislocation structures of α precipitates in a Ti–7.26 wt.% Cr alloy

Effect of temperature on the specific energy of β / α interfaces in Ti-6Al-4V alloy

The Effect of β Stabilizers on the Structure and Energy of α/β Interfaces in Titanium Alloys

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