Reversion of a Parent {130}⟨310⟩α′′ Martensitic Twinning

Abstract

In bcc metastable β titanium alloys, and particularly in superelastic alloys, a unique {332}⟨113⟩ twinning system occurs during plastic deformation. However, in situ synchrotron x-ray diffraction during a tensile test shows that the β phase totally transforms into α^{''} martensite under stress in a Ti-27Nb (at. %) alloy. {332}⟨113⟩_{β} twins are thus not formed directly in the β phase but are the result of the reversion of {130}⟨310⟩_{α^{''}} parent twins occurring in martensite under stress. The formation of an interfacial twin boundary ω phase is also observed to accommodate strains induced during the phase reversion.

Stress release-induced interfacial twin boundary ω phase formation in a β type Ti-based single crystal displaying stress-induced α” martensitic transformation

“…Depending on different historical processes, the particle morphologies of ω phase can be ellipsoidal or cuboidal after ageing [10][11][12] and plate-like in strained titanium alloys [13][14][15]. These morphological differences for ω phase can be attributed to both compositional partition and stressing condition [10][11][12][16][17][18]. However, the model of collapsing one pair of {1 1 1} β planes to an intermediate position leaving the adjacent {1 1 1} β planes unaltered were proved and widely accepted as the formation mechanism of ω phase for nearly all cases [3,19,20].…”

“…However, the model of collapsing one pair of {1 1 1} β planes to an intermediate position leaving the adjacent {1 1 1} β planes unaltered were proved and widely accepted as the formation mechanism of ω phase for nearly all cases [3,19,20]. Amongst them, thin layer ω phase located along the twin boundary, which was called ITB-ω [18], deserves more investigation. The two twinning systems observed in β-type Ti alloys are {1 1 2} <1 1 1> β [18,19,[21][22][23][24][25] and {3 3 2} <1 1 3> β [26][27][28][29][30][31].…”

Effects of {332}〈113〉 Deformation Twinning on Fatigue Behavior of Ti–Mn System Alloys

“…35,36) Recently, Gloriant et al 37) and Tsuchiya et al 38) have reported tensile deformation behavior of TiNb and TiMo alloys, respectively, focusing on the formation of {332}©113ª deformation twins. Similarly, Raabe et al 39) and Gloriant et al 40) have studied formation mechanism of the {332}©113ª twins in TiNb alloys. Tobe et al 41) have reported possible twinning modes in metastable ¢-type Ti alloys based on the theory of the crystallography of deformation twinning.…”

Twinning behavior of orthorhombic-α” martensite in a Ti-7.5Mo alloy

“…The activation of these twinning modes strongly depends on the lattice parameters of β and αʺ martensite [19,28]. For instance, Inamura et al [19] reported the activation of different twinning modes in Ti- (33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)Nb-3Al (wt.%) alloys, namely {111} α"type I, <211> αʺ -type II and {011} αʺ -compound twinning, which is associated with Nb content.…”

“…Accordingly, a better understanding of deformation mechanisms of αʺ martensite is essential for the development of high-performance alloys [6,[31][32][33]. So far, few studies have analyzed deformation behaviors of αʺ martensite in β-Ti alloys [25,34,35]. These studies have reported {130} αʺ -compound twinning in a Ti-25Ta-20Nb (wt.%) alloy [25], and {130} αʺ -compound and {103} αʺ -compound twinning in a Ti-42Nb (wt.%) alloy [34].…”