The shock and spall response of three industrially important hexagonal close-packed metals: magnesium, titanium and zirconium

Abstract

Magnesium, titanium and zirconium and their alloys are extensively used in industrial and military applications where they would be subjected to extreme environments of high stress and strain-rate loading. Their hexagonal close-packed (HCP) crystal lattice structures present interesting challenges for optimizing their mechanical response under such loading conditions. In this paper, we review how these materials respond to shock loading via plate-impact experiments. We also discuss the relationship between a heterogeneous and anisotropic microstructure, typical of HCP materials, and the directional dependency of the elastic limit and, in some cases, the strength prior to failure.

Modelling and characterization of cell collapse in aluminium foams during dynamic loading

“…However, most of previous researchers overlook the complex geometrical structure and localized deformation of the cell walls that will significantly affect the predicted results. It can be noted that, previously, studies have been carried out to investigate the impact and shock response of solid metals [25][26][27][28][29][30][31] and ceramics [32]. In contrast, there is a paucity of similar data for metal foams.…”

Twin boundary activated α → ω phase transformation in titanium under shock compression

“…The plastic deformation of hcp metals is dominated by the movement of a  dislocations with the shortest Burgers vector: 1210  . In quasi-static deformed α-Ti, the easiest slip mode is prismatic{1010} 1210  , and the basal slip and the first order pyramidal slip operate as the less prominent slip modes [7,37], inidcated as P, B and π in Fig. 5(a), repectively.…”

“…It is well known that microstructure affects the response of a material to dynamic loading as dislocations, stack faults, grain boundaries (GBs) and other heterogeneities can act as defect sites that can promote plastic deformation and phase transformation [1][2][3][4][5]. The behavior of GBs under dynamic mechanical loads is of particular interest as it impacts the bulk properties of polycrystal materials in many respects [2,[6][7]. In particular, when the grain size is reduced to ultrafine or nano-scale, the effects of GBs on the material properties become more significant since the traditional deformation mechanisms based on nucleation and propagation of dislocations are replaced gradually by GB mediated processes, such as GB sliding [8][9], grain rotation [10][11], dislocation nucleation or absorption at GBs etc [2,12].…”

Deformation and spallation of a magnesium alloy under high strain rate loading

“…Normally used as die cast products (e.g., AZ91), they offer a combination of desirable mechanical properties, castability and corrosion resistance [3,4]. During service, magnesium alloys may be subjected to impulsive loading such as impact, and their dynamic responses under high strain rate loading have been investigated with split Hopkinson compression or tension bars (10 2 −10 4 s −1 ) [5,6,7,8,9], and to a lesser extent, with gas gun plate impact at higher strain rates (∼10 5 s −1 or higher) [10,11,12,13,14,15].…”