Deformation‐mechanism maps of the intermetallic compound MgZn₂

Abstract

Dedicated to Professor Hermann NEELS on the occasion of his 65th birthday Stress-temperature curves at constant strain-rate have been summarized for steady-state flow conditions of single crystals and polycrystals, and fields of dominating microscopic mechanisms were proposed.Fur stationare FlieObedingungen von Ein-und Vielkristallen werden Spannurigs-Temperatur-Kurven bei konstanter Verformungsgeschwindigkeit und Felder dominierender mikroskopischer Mechanismen angegeben.

On the structure of defects in the Fe7Mo6 μ-Phase

“…Indeed, Krämer and Schulze [21] have reported -based on geometrical considerations -that deformation of Laves phases can occur by perfect dislocation glide of dislocations with a Burgers vector of 1 3 〈112 � 0〉 on basal and prismatic planes. This slip mode has been experimentally confirmed by several groups at temperatures above a homologous temperature of 0.6 Tm for the respective Laves phases [22,23,32,40]. As evident from Figure 8b, glide of a perfect dislocation with a Burgers vector 1 3 〈112 � 0〉 on the basal plane creates no stacking fault since a full translation of the lattice is created.…”

“…Krämer et al [21] have suggested that the Peierls barrier is very high in TCP phases due to their close and complex packing ('interlocking'). This is well described for the Laves phases [21][22][23][24][25][26], the most common group of TCP-phases, which are themselves also composed of a layered structure, i.e. an alternating stacking sequence of single and triple layers.…”

Early work on Laves phases in East Germany

“…For other strain rates cf. [137]. The influence of Zn composition is also indicated (after Paufler [137]).…”

“…Summarizing the mechanical response of the hexagonal Laves phase MgZn 2 , deformation mechanism maps have been proposed [137]. Fig.…”

Laves-phase superalloys?

“…With an etch-pit technique, dislocation velocity versus stress data were obtained on both basal and prism planes [27,28]. This group also published extensive data on stress-strain behavior, creep, dislocation densities, slip bands, twinning, diffusion, deformation-mechanism maps [30], and the effect of varying stoichiometry (from 66.0 to 67.5 at% Zn) on dislocation behavior and mechanical properties [29]. However, as with MgCu, crystals, plastic deformation in MgZn, crystals was limited to temperatures above about 0.65Tm.…”