Deformation and melting of steel projectiles in hypervelocity cratering experiments

Kenkmann, T.; Trullenque, Ghislain; Deutsch, Alexander; Hecht, Lutz; Ebert, Matthias; Salge, T.; Schäfer, F.; Thoma, Klaus

doi:10.1111/maps.12018

Cited by 21 publications

(29 citation statements)

References 41 publications

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“…This is counter to the observations made for ductile (i.e. metal) projectiles by Hernandez, Murr & Anchondo (2006), Kenkmann et al (2013) and McDermott et al (in preparation). This suggests that the fracturing mechanism between lithological projectiles (non-ductile) and metallic (ductile) projectiles is different.…”

Section: Discussioncontrasting

confidence: 54%

Survival of the impactor during hypervelocity collisions – I. An analogue for low porosity targets

Avdellidou¹,

Price²,

Delbò³

et al. 2015

Mon. Not. R. Astron. Soc.

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Recent observations of asteroidal surfaces indicate the presence of materials that do not match the bulk lithology of the body. A possible explanation for the presence of these exogenous materials is that they are products of inter-asteroid impacts in the Main Belt, and thus interest has increased in understanding the fate of the projectile during hypervelocity impacts. In order to gain insight into the fate of impactor we have carried out a laboratory programme, covering the velocity range of 0.38 -3.50 km/s, devoted to measuring the survivability, fragmentation and final state of the impactor. Forsterite olivine and synthetic basalt projectiles were fired onto low porosity (<10%) pure water-ice targets using the University of Kent's Light Gas Gun (LGG). We developed a novel method to identify impactor fragments which were found in ejecta and implanted into the target. We applied astronomical photometry techniques, using the SOURCE EXTRACTOR software, to automatically measure the dimensions of thousands of fragments. This procedure enabled us to estimate the implanted mass on the target body, which was found to be a few percent of the initial mass of the impactor. We calculated an order of magnitude difference in the energy density of catastrophic disruption, Q*, between peridot and basalt projectiles. However, we found very similar behaviour of the size frequency distributions for the hypervelocity shots (>1 km/s). After each shot, we examined the largest peridot fragments with Raman spectroscopy and no melt or alteration in the final state of the projectile was observed.

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Section: Discussioncontrasting

confidence: 54%

Survival of the impactor during hypervelocity collisions – I. An analogue for low porosity targets

Avdellidou¹,

Price²,

Delbò³

et al. 2015

Mon. Not. R. Astron. Soc.

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“…Vice versa, residual internal strain is reasonably related to episodes of intense stress conditions without an adequate annealing experienced by the meteorites after crystallization. Asteroidal hypervelocity impacts with fragmentation of the solidified material, followed by an insufficient annealing time would account for these conditions [29]. Accordingly, meteorites characterized by evident plastic deformation, such as Chinga [30] and Mont Dieu [31], present the highest value of internal strain.…”

Section: Resultsmentioning

confidence: 99%

Different Conditions of Formation Experienced by Iron Meteorites as Suggested by Neutron Diffraction Investigation

et al. 2018

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Abstract:In this communication, we report the results of a preliminary neutron diffraction investigation of iron meteorites. These planetary materials are mainly constituted by metallic iron with variable nickel contents, and, owing to their peculiar genesis, are considered to offer the best constrains on the early stages of planetary accretion. Nine different iron meteorites, representative of different chemical and structural groups, thought to have been formed in very different pressure and temperature conditions, were investigated, evidencing variances in crystallites size, texturing, and residual strain. The variability of these parameters and their relationship, were discussed in respect to possible diverse range of petrological conditions, mainly pressure and cooling rate, experienced by these materials during the crystallization stage and/or as consequence of post accretion events.

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“…Other, more recent, work (Kenkmann et al, 2013) investigated 10-12 mm diameter steel sphere projectile deformation during hypervelocity impacts at 2.5-5.3 km s À1 into wet and dry sandstone blocks. They reported no significant trend between impact energy, the presence of water in the target and the mass of the projectile recovered after impact.…”

Section: Comparison To Other Laboratory Experimentsmentioning

confidence: 98%

“…However, projectile fragmentation appeared to increase if the target contained substantial amounts of water, suggesting that the shock history played an important role in the fragmentation. In impacts on dry sandstone at speeds up to 5.34 km s À1 , Kenkmann et al (2013) typically recovered over 70% of the impactor mass from the crater, usually in a single large bowl-shaped fragment. However, if the sandstone contained water (with thus a different shock history during the impact) multiple fragments were obtained, and in one case at 5.7 km s À1 , the fragments were described as ''tiny", each being less than 10% of the original projectile diameter.…”

Section: Comparison To Other Laboratory Experimentsmentioning

confidence: 99%

“…Thus the projectile fate is a relatively neglected field of study. There are some exceptions to this, such as work by Hernandez et al (2006), Kenkmann et al (2013) and Ebert et al (2014) which investigated the processes that occur between the target and projectile during hypervelocity impacts. Or, for example, by Bowden et al (2008) and Parnell et al (2010) who looked for survival of biomarkers in projectile fragments which survived impacts, and Burchell et al (2014a) who looked for transfer of volatiles to targets after impacts.…”

Section: Introductionmentioning

confidence: 95%

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Survivability of copper projectiles during hypervelocity impacts in porous ice: A laboratory investigation of the survivability of projectiles impacting comets or other bodies

McDermott

Price

Cole

et al. 2016

Icarus

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a b s t r a c tDuring hypervelocity impact (>a few km s À1 ) the resulting cratering and/or disruption of the target body often outweighs interest on the outcome of the projectile material, with the majority of projectiles assumed to be vaporised. However, on Earth, fragments, often metallic, have been recovered from impact sites, meaning that metallic projectile fragments may survive a hypervelocity impact and still exist within the wall, floor and/or ejecta of the impact crater post-impact. The discovery of the remnant impactor composition within the craters of asteroids, planets and comets could provide further information regarding the impact history of a body. Accordingly, we study in the laboratory the survivability of 1 and 2 mm diameter copper projectiles fired onto ice at speeds between 1.00 and 7.05 km s À1 . The projectile was recovered intact at speeds up to 1.50 km s À1 , with no ductile deformation, but some surface pitting was observed. At 2.39 km s À1 , the projectile showed increasing ductile deformation and broke into two parts. Above velocities of 2.60 km s À1 increasing numbers of projectile fragments were identified post impact, with the mean size of the fragments decreasing with increasing impact velocity. The decrease in size also corresponds with an increase in the number of projectile fragments recovered, as with increasing shock pressure the projectile material is more intensely disrupted, producing smaller and more numerous fragments. The damage to the projectile is divided into four classes with increasing speed and shock pressure: (1) minimal damage, (2) ductile deformation, start of break up, (3) increasing fragmentation, and (4) complete fragmentation. The implications of such behaviour is considered for specific examples of impacts of metallic impactors onto Solar System bodies, including LCROSS impacting the Moon, iron meteorites onto Mars and NASA's ''Deep Impact" mission where a spacecraft impacted a comet.

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Deformation and melting of steel projectiles in hypervelocity cratering experiments

Cited by 21 publications

References 41 publications

Survival of the impactor during hypervelocity collisions – I. An analogue for low porosity targets

Survival of the impactor during hypervelocity collisions – I. An analogue for low porosity targets

Different Conditions of Formation Experienced by Iron Meteorites as Suggested by Neutron Diffraction Investigation

Survivability of copper projectiles during hypervelocity impacts in porous ice: A laboratory investigation of the survivability of projectiles impacting comets or other bodies

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