Elastic-plastic deformation and spall fracture of metals at high temperatures

“…The HEL values were calculated from the measured free surface velocity using Equation (1). [25] From the HEL, we approximated the equivalent quasi-static elastic limits as 0.97, 1.02, and 1.02 GPa, respectively using Equation (2). [25] These values are consistent with the previously reported quasi-static elastic limits measured of the HIP and heat-treated material in compression (Figure 1a of ).…”

Section: Resultsmentioning

confidence: 99%

“…[25] From the HEL, we approximated the equivalent quasi-static elastic limits as 0.97, 1.02, and 1.02 GPa, respectively using Equation (2). [25] These values are consistent with the previously reported quasi-static elastic limits measured of the HIP and heat-treated material in compression (Figure 1a of ). [21] In those previous experiments, using in situ synchrotron X-ray diffraction, it was shown that these elastic limit strength values correspond with the onset of (mostly) reversible stressinduced martensitic transformation, not plasticity.…”

Section: Resultsmentioning

confidence: 99%

Mechanisms of Shock Strength Exhibited by a Nickel‐Rich Nickel‐Titanium‐Hafnium Alloy

Knapp,

Amin-Ahmadi,

Turnage

et al. 2023

Adv Eng Mater

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Nickel‐rich NiTiHf alloys that are heat treated to strengthen the microstructures with a dense distribution of Ni4Ti3 nanoprecipitates exhibit very high strengths and good quasi‐static indentation resistance and rolling contact fatigue performances. To determine whether these properties are maintained at high rates of loading, in‐situ and recovery flyer plate impact shock experiments were performed on a Ni54Ti45Hf1 alloy at impact velocities ranging from approximately 150 m/s (2.5 GPa) to 700 m/s (12.40 GPa). Analysis of shocked samples indicated less cracking was observed to emanate from spall failures resulting from impact velocities greater than 250 m/s (4.23 GPa), concurrent with observations of intragranular microbands within the microstructures. Analyses showed clear evidence that, like responses to quasi‐static loading, martensitic phase transformation occurred upon shock compression in all cases. However, dissimilarly, for the higher impact velocities it reversed upon stress release, leaving behind microbands that showed no evidence for retained martensite and within which the Ni4Ti3 nanoprecipitates dissolved. These results indicate that strain‐rate dependence of these SMAs under shock loading are not only governed by expected physics of rate‐dependence of the martensitic transformations themselves but may also be enhanced by inelastic deformation mechanisms that result in precipitate dissolution.This article is protected by copyright. All rights reserved.

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“…In [67][68][69], involving specimens subjected to explosive loading, the authors report a decrease in the spall strength of St.3 and Cu with increasing initial temperature (up to 500 • C).…”

Section: Temperature Dependence Of σ Spallmentioning

confidence: 99%

Dynamic Strength of Materials

Glushak¹,

Tyupanova²,

Bat'kov³

2006

Material Properties Under Intensive Dynamic Loading

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The methods used in practice for the acquisition and interpretation of experimental data pertaining to the resistance of materials to plastic-strain (shearstrength) are based on the concepts of the nature of motion of a material possessing strength and the features of high-rate deformation discussed in Chap. 1. These methods are briefly described below. Additional information on this topic is available to the reader in monographs [1-3], review [4], and the original papers cited in [1-4]. Comparison between the Shock Hugoniot and the Hydrostatic Compression IsothermGiven two assumptions: (1) material strength is isotropic, and (2) the difference between isothermal hydrostatic compression and the mean stress σ ii /3 is small, the dynamic yield strength is calculated to be the difference between the stress σ 1 on the elastic-plastic shock Hugoniot and the pressure P on the hydrostatic compression isotherm (given in terms of specific volume V (or strain ε)) as Y d = 3(σ 1 − P )/2. This approach to the estimation of Y d is limited to cases wherein the stresses σ 1 are relatively low, and the temperature rise during shock compression is modest (resulting in a thermal component of pressure that is low in comparison to the total pressure).For the aluminum alloy Al-2024, [5] recommends that for shock pressures in the 2.7 GPa ≤ σ 1 ≤ 9.4 GPa range, one should use the following relations for σ 1 (ε) (the normal stress component in a plane wave shock) and P (ε) (the hydrostatic compression) in calculations of the dynamic yield strength: σ 1 = 0.18 + 72.06ε − 347.1ε 2 (GPa); P = 75.9ε + 201ε 2 (GPa). This method for the evaluation of Y d , among other things, requires a highly accurate determination of the curves σ 1 (ε) and P (ε) since minor changes in ε can lead to significant changes in σ 1 and P .

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Elastic-plastic deformation and spall fracture of metals at high temperatures

Cited by 14 publications

References 2 publications

Use of laser-accelerated foils for impact study of dynamic material behaviour

Use of laser-accelerated foils for impact study of dynamic material behaviour

Mechanisms of Shock Strength Exhibited by a Nickel‐Rich Nickel‐Titanium‐Hafnium Alloy

Dynamic Strength of Materials

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