Shock-wave compression

Johnson Q and Mitchell A C 1972 First x-ray diffraction evidence for a phase transition during shock-wave compression Phys. Rev. Lett. 29 1369... 

Grady, D.E. (1977), Processes Occurring on Shock Wave Compression of Rocks and Minerals, in High Pressure Research Applications in Geophysics (edited by Manghnani M.H. and S. Akimoto), Academic Press, New York, pp. 389-438. 

Wackerle, J. (1962), Shock-Wave Compression of Quartz, J. Appl. Phys. 33,922-937. 

The structure/property relationships in materials subjected to shock-wave deformation is physically very difficult to conduct and complex to interpret due to the dynamic nature of the shock process and the very short time of the test. Due to these imposed constraints, most real-time shock-process measurements are limited to studying the interactions of the transmitted waves arrival at the free surface. To augment these in situ wave-profile measurements, shock-recovery techniques were developed in the late 1950s to assess experimentally the residual effects of shock-wave compression on materials. The object of soft-recovery experiments is to examine the terminal structure/property relationships of a material that has been subjected to a known uniaxial shock history, then returned to an ambient pressure... 

The lone remaining aspect of this topic that requires additional discussion is the fact that the mechanical threshold stress evolution is path-dependent. The fact that (df/dy)o in (7.41) is a function of y means that computations of material behavior must follow the actual high-rate deformational path to obtain the material strength f. This becomes a practical problem only in dealing with shock-wave compression. 

An important aspect of micromechanical evolution under conditions of shock-wave compression is the influence of shock-wave amplitude and pulse duration on residual strength. These effects are usually determined by shock-recovery experiments, a subject treated elsewhere in this book. Nevertheless, there are aspects of this subject that fit naturally into concepts associated with micromechanical constitutive behavior as discussed in this chapter. A brief discussion of shock-amplitude and pulse-duration hardening is presented here. 

That some enhancement of local temperature is required for explosive initiation on the time scale of shock-wave compression is obvious. Micromechanical considerations are important in establishing detailed cause-effect relationships. Johnson [51] gives an analysis of how thermal conduction and pressure variation also contribute to thermal explosion times. 

The general subject of solid-state chemical reaction in shock-wave compression, or shock-wave synthesis, has recently become an important part of the... 

Shock-wave compression is also used to study solid-solid phase transformation. Bancroft et al. [58] report a previously unknown phase transformation... 

One cannot emphasize too strongly the importance of direct, time-resolved experimental observation of microscale phenomena in establishing sound theories of microstructural effects under conditions of shock-wave compression. 

Underlying all continuum and mesoscale descriptions of shock-wave compression of solids is the microscale. Physical processes on the microscale control observed dynamic material behavior in subtle ways sometimes in ways that do not fit nicely with simple preconceived macroscale ideas. The repeated cycle of experiment and theory slowly reveals the micromechanical nature of the shock-compression process. 

J.J. Dick and D.L. Styrus, Electrical Resistivity of Silver Foils Under Uniaxial Shock-Wave Compression, J. Appl. Phys. 46, 1602-1617 (1975). 

Q. Johnson and A. Mitchell, R.N. Keeler, and L. Evans, X-Ray Diffraction During Shock-Wave Compression, Phys. Rev. Lett. 25, 1099-1101 (1970). 

Crystals Undergoing Shock-Wave Compression, Appl. Phys. Lett. 21, 29-30 (1972). 

Q. Johnson and A.C. Mitchell, First X-Ray Diffraction Evidence for a Phase Transition During Shock-Wave Compression Phys. Rev. Lett. 29, 1369-1371. 

Adadurov, G.A. and Gol danskii, V.I., Transformations of Condensed Substances Under Shock-Wave Compression in Controlled Thermodynamic Conditions, Russian Chem. Rev. 50 (10), 848-957 (1981). 

Curran [61C01] has pointed out that under certain unusual conditions the second-order phase transition might cause a cusp in the stress-volume relation resulting in a multiple wave structure, as is the case for a first-order transition. His shock-wave compression measurements on Invar (36-wt% Ni-Fe) showed large compressibilities in the low stress region but no distinct transition. 

The experiments result in an explicit measure of the change in the shock-wave compressibility which occurs at 2.5 GPa. For the small compressions involved (2% at 2.5 GPa), the shock-wave compression is adiabatic to a very close approximation. Thus, the isothermal compressibility Akj- can be computed from the thermodynamic relation between adiabatic and isothermal compressibilities. Furthermore, from the pressure and temperature of the transition, the coefficient dO/dP can be computed. The evaluation of both Akj-and dO/dP allow the change in thermal expansion and specific heat to be computed from Eq. (5.8) and (5.9), and a complete description of the properties of the transition is then obtained. 

M. Ross and H. B. Radousky, Shock wave compression and metallization of simple molecules , in Simple Molecular Systems at Very High Density, A. Polian, P. Loubeyre, and N. Boccara, eds.. Plenum Press, New York, 1989, pp. 47—56. 

Since the detonation velocity is equal to the speed of sound at the CJ point, Wp is determined by means of Eqs. (3.24) and (3.25). The temperature of detonation at the CJ point is higher than the temperature of deflagration because of the shock wave compression on the detonation wave. 

Shock Wave Compressions of Twenty-Seven Metals , PhysRev 108, 196-216 (Oct 2, 1957)... 

Refs 1) J.M. Walsh et al, "Shock-Wave Compressions of Twenty-Seven Metals. Equations of State of Metals , PhysRev 108, 196(1957) 2) Cook (1958), p 206... 

MAF 24, 443-50(1950) CA 45, 8772(1951) (Present state and value of the hydrothermo-dynamic theory of explosions and shocks, I. The plane shock waves compressibility by shock without combustion) 17) Ibid 25, 421-624 923-1006(1951) (Thickness of shock waves and mechanism of inflammation in combustion waves) 18) T. VonKarmdn, Termotecnica (Milan) 5(2),... 

R.F. Chisnell, Ibid 2-3, 296-98(1957) (Motion of shock wave in a channel with applications to cylindrical and spherical shock waves) 43) J.M. Walsh et al, PhysRev 108(2), 196-216(Oct 1957) (Shock wave compression of 27 metals) 44) J.J. 

The cubic y-modification has been recently observed under a pressure of 15 GPa and temperatures above 2000 K by the laser heating technique in a diamond cell [23] and in shock-wave compression experiments with pressures >33 GPa at 1800 K and >50 GPa at 2400 K [29]. This modification is often designated as the c-modification in the literature in analogy to the cubic boron nitride (c-BN). It has a spinel-type structure in which two silicon atoms are octahedrally coordinated by six nitrogen atoms, one silicon atom is coordinated tetrahedrally by four nitrogen atoms (Fig. 3c). The atomic coordinates for the cubic modification are given in Table 2. From calculations it is shown that this structure should have a high hardness similar to that of diamond and c-BN [23]. 

Static and shock wave compressions are the two remarkably different ways for generating pressures above 1 GPa. Here, only apparatus generating static pressures of more general use will be considered. These are classified into several types, piston-cylinder, Bridgman anvU, belt, multi-anvil, and cascaded multi-anvil types. The available pressure range depends on the type and also on the volume of the sample chamber used. It is 2 4 GPa with the piston-cylinder type, 5-8 GPa with the belt type, 10-20GPa with... 

It is evident from the phase diagram that diamond may be obtained in a very wide pressure-temperature range, thus allowing several synthesizing methods to work in various regions. Those mainly applied are conversion of graphite to diamond by a flux method, direct conversion by shock wave compression, and direct conversion by static compression. Synthetic diamond is mostly produced by the flux method, which will be outlined below. 

McQueen R. G. and Marsh S. P. (1966) Shock-wave compression of iron-nickel alloys and the Earth s core. J. Geophys. Res. 71, 1751-1756. 

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