Effects of ordering type and degree on monoclinic distortion of 18R-type martensite in Cu-Zn-Al alloys

Ordering transitions in quenched Au7Cu5Al4 alloy and effect of order on martensitic transformation

“…In contrast, an increase in the order at next nearest neighbors, L2 1 , increases the M S temperature [8,15,16]. It caused by the relation between the ordering structure and the orthorhombic distortion for the martensite [17]. It is found [17] that an increase of ordering at nearest neighbors (B2) increases the orthorhombic distortion, but on the contrary an increase on the degree order at next nearest neighbors (L2 1 ) decreases the orthorhombic distortion.…”

“…It caused by the relation between the ordering structure and the orthorhombic distortion for the martensite [17]. It is found [17] that an increase of ordering at nearest neighbors (B2) increases the orthorhombic distortion, but on the contrary an increase on the degree order at next nearest neighbors (L2 1 ) decreases the orthorhombic distortion. Furthermore, it has been verified that these two stages in the orthorhombic distortion behavior are linked to a decrease and an increase of M S temperatures, respectively, in both Cu-Zn-Al [18], and Cu-Al-Ni [16] alloys.…”

Aging effects in a Cu-12Al-5Ni-2Mn-1Ti shape memory alloy

“…[15,26,36] This tentative interpretation, however, easily yields controversial or even misleading conclusions. [26] The close-packed planes will be inherited by martensite as the basal planes of the LPSO structure. For bcc disordered, B2 ordered, D0 3 ordered, and L2 1 ordered parent phase unit cells, the atomic configurations in the close-packed {110} planes are shown in Figure 16.…”

“…In the bcc-type structure, lattice points can be generally separated into I, II, and III sublattices. [26] Obviously, the type and degree of atomic order and the alloy composition will decide the atomic arrangements in the basal planes and, in turn, the lattice constants a and b. If an alloy is not in the ideally ordered state, the atom arrangements on the sublattice will depend on the degree of atomic order.…”

Structural and Morphological Investigations on Shape Memory CuZnAl Alloys

“…The martensitic transformation in copper-based alloys is thermoelastic, that is, the transformation progresses following the undercooling below the equilibrium temperature. In addition, a hysteresis is observed because of irreversible processes taking place during the transformation-retransformation path [1][2][3]. The martensitic phases can be either thermally-induced, spontaneous transformation, or stress-induced, cooling or stressing the β phase.…”