Acoustic emission from zinc deformed at room temperature Part I The influence of strain rate on deformation behaviour and acoustic emission in pure zinc

Influence of the Microstructure of the Initial Material on the Zn Wires Prepared by Direct Extrusion with a Huge Extrusion Ratio

“…Coarse-grained materials are more sensitive to twinning or the formation of shear bands. Such microstructural defects can act as initiation sites for recrystallization and the formation of fine-grained bands, and chains can be expected in coarse-grained materials deformed at elevated temperatures [9,14,[28][29][30]. On the other hand, more intensive and homogeneous dynamic recrystallization is usually observed in the case of materials with finer microstructures.…”

“…This makes the connection between the formation of cleavage cracks and the serration on the tensile curves improbable. The tendency towards twinning can be explained by the large grain size, which decreases the critical resolved shear stress (CRSS) for twinning [9,28]. Interesting findings were collected in the case of the wires extruded at 100 • C. Higher TYS and UTS were observed for the MG_Ex 100 • C, even though this wire possessed a significantly coarser microstructure than the CG_Ex 100 • C. The differences in TYS can be explained by the differences in texture and consequently by the differences in the Schmid factor for the basal slip (the predominant deformation mechanism in zinc [35]).…”

“…The main drawback of zinc and its alloys is their poor strength (~30 MPa, pure zinc) and ductility (~0.25%, pure zinc) [7,8] in the as-cast state. Cast zinc is usually coarsegrained; the increasing grain size decreases the critical resolved shear stress (CRSS) for twinning, which is the predominant deformation mechanism in coarse-grained Zn-based materials [9]. The extensive twinning leads to the twin-twin and twin-dislocation interactions, resulting in the formation of cracks and a subsequent decrease in ductility [10,11].…”

“…The medium-grained Zn-based materials deform mainly by dislocation slip, which results in an increase in both strength and ductility [9,12]. Another decrease in the grain-size can lead to a decrease in strength and increase in ductility due to the activation of the creep-like deformation mechanisms (dislocation climb, grain boundary sliding) [9,13]. The aforementioned suggests that a suitable adjustment of the grain size can alter the mechanical performance to be closer to the values desired for applications.…”

A study on galling initiation in friction coupling stretch bending with advanced high strength hot-dip galvanized sheet

“…It is thus impossible to achieve Sliding distance terminated at: compatible deformation between zinc coating and substrate in the friction coupling plastic bending process. Chmelick et al [23] estimated that pure zinc had yield strength of 30 MPa and gave maximum elongation of about 18%. Furthermore, the poor ductility of zinc layer makes it susceptible to crack during deformation when the coupling die is relatively rough (Fig.…”