Compression wave studies on calcite rock

Abstract

Dynamic compression wave studies have been conducted on three calcite rocks, Solenhofen limestone, Oakhall limestone, and Vermont marble, in the stress range of 0–5 GPa. Plate impact techniques provided transient stress wave input, and diffuse laser interferometry was used to study the evolution of these pulses through various thicknesses of rock. Both loading response and release wave response were determined from the time‐resolved particle velocity profiles. The calcite I–II and II–III phase transitions dramatically influence wave propagation in this stress region. The I–II transition begins between 0.6 and 1.2 GPa depending on rock type and is found to be consistent with a reversible, displacive polymorphic phase change. A constitutive model based on stress heterogeneity describes most of the features associated with the I–II transition. The calcite II–III transition proceeds above 2.4 GPa, and peak stress values traverse a metastable Hugoniot. This wave feature and others are more characteristic of a slower, reconstructive phase change. We conclude that stress wave features reveal striking differences in the nature of the shock‐induced calcite transitions and that these transitions strongly influence the dynamic constitutive behavior of calcite rock.

On the encounter of an acoustic shear pulse with a phase boundary in an elastic material: reflection and transmission behavior

“…The recent literature on this subject is now extensive; one may refer to [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19], [34,35] and their associated references. The resulting mechanical response replicates material behavior as observed in a host of important materials including crystalline solids [20,21], shape memory alloys [22], polymers and rubber [23]. It has been suggested that this theory may describe the mechanical behavior associated with elastic-plastic material response and with the pseudo-elastic shape memory effect [15,16].…”

Shock temperature in calcite (CaCO3) at 95–160 GPa

“…10 is applicable at high pressure even when calcite (high-pressure phase) is completely transformed to CaO and CO 2 , i.e., K becomes 1. Previous shock wave measurements reported that calcite undergoes three phase transitions: calcite I to II transition between 0.6 and 1.2 GPa, calcite II to III transition around 2.4 GPa, and III to IV transition around 10 GPa [20,29]. We have used the isentrope of phase IV as the reference state.…”

On the Asymptotic Analysis of Travelling Shocks and Phase Boundaries in Elastic Bars.

“…The problem is introduced in section II, where it is reviewed how change of phase phenomena can be modelled by means of a nonmonotonic stress-strain law. These laws have been studied previously in [1], [2], [3]; a relevant experimental study is (4].…”

“…The separated strain intervals are now associated with different material phases. Here the value of the transition stress a is assumed to be a property of the material (see [4] S"The condition (2.4) indicates that the bar is taken to be initially undeformed and at rest. The condition (2.3) can also be written…”