Final Report 02-ERD-033: Rapid Resolidification of Metals using Dynamic Compression

Streitz, Frederick H.; Nguyen, Jeffrey H.; Orlikowski, Daniel; Roger, Michel; Moriarty, John A.; Holmes, N. C.

doi:10.2172/15014719

Cited by 4 publications

(5 citation statements)

References 15 publications

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“…4 A numerical simulation recently demonstrated the existence of this phase in a solidifying Ta melt. 5 These reasons, together with the industrial importance ͑e.g., aerospace, electronic, machine tools͒ of tantalum and rhenium have motivated the measurement of their densities for a long time. However, their refractory nature, the lack of suitable crucibles, severe chemical reaction, and contamination, have limited the measurement of reliable data only at their melting points ͑Ta: 3290 K, Re: 3453 K͒ 6 when using the pendant drop method.…”

Section: Noncontact Density Measurements Of Tantalum and Rhenium In Tmentioning

confidence: 99%

Noncontact density measurements of tantalum and rhenium in the liquid and undercooled states

Paradis¹,

Ishikawa²,

Yoda³

2003

Applied Physics Letters

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Electrostatic levitation together with multibeam heating and ultraviolet imaging overcame contamination, imaging, and sample position stability problems associated with handling of liquid tantalum and rhenium. Here, the density [ρ(T)] of these metals is reported in the superheated and undercooled states. Over the 2760–3580 K interval, the density of tantalum was measured as ρ(T)=1.50×104−0.41(T−Tm) kg m−3, where the melting temperature Tm, was 3290 K. For rhenium, the density was determined (2700–3810 K) as ρ(T)=1.84×104−0.91(T−Tm), with Tm=3453 K. From these data, respective volume expansion coefficients of 2.7×10−5 and 4.9×10−5 K−1 were calculated. At Tm, the data agree well with the literature values.

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Section: Noncontact Density Measurements Of Tantalum and Rhenium In Tmentioning

confidence: 99%

Noncontact density measurements of tantalum and rhenium in the liquid and undercooled states

Paradis¹,

Ishikawa²,

Yoda³

2003

Applied Physics Letters

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“…20 Sn, 21,22 and water. [23][24][25] Measurements with such diagnostics as laser velocimetry and high-speed photography suggest both homogeneous and heterogeneous crystallization during shock or quasi-isentropic compression.…”

Section: Introductionmentioning

confidence: 99%

Homogeneous crystal nucleation in liquid copper under quasi-isentropic compression

Cai

Wang

et al. 2015

Phys. Rev. B

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Shock-induced freezing in liquids has long been a subject of interest as well as mystery. With large-scale molecular dynamics simulations, we demonstrate that homogeneous crystal nucleation in liquid Cu can be realized under certain supercooling (θ), via quasi-isentropic compression or ramp wave loading with a particle velocity u p achieved within a ramp time τ . The simulations yield the τ -u p -θ relations for homogeneous crystallization at the spatial and temporal scales of molecular dynamics; a ramp wave loading with τ ∼ 100 ps is essentially isentropic for liquid Cu. Based on classical nucleation theory, we predict θ, and thus u p , as required for homogenous nucleation in experiments with larger length and time scales. Homogeneous nucleation can also be achieved with shock loading in initially sueprcooled liquids.

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“…The wave velocity was measured by two channel digital storage oscilloscope (TDS2022, Tektronix, Beaverton, USA). The wave acoustic impedance, Z and the elastic modulus, E are calculated according to the formulas [9]. 2a).…”

Section: Methodsmentioning

confidence: 99%

“…Graded density impactors with all kinds of system have been reported. Martin et al [9] have successfully fabricated graded density impactors with density range from 0.1gcm -3 to 15gcm -3 . Foam resin composites, resin filled with metal particles, and alloys have been used as low, medium, and high materials.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Properties of Aluminum-Copper Composites Prepared by Hot-Pressure Sintering

Zhang

Xiao

Luo

et al. 2014

KEM

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Aluminum (Al) and Copper (Cu) have been used in graded density impactors. Al-Cu composites with different compositions have been prepared by hot pressing sintering. Intermetallic compounds were produced when the temperature was above 723 K, while they can’t be found at the temperature of 723 K. The relative density of Al-Cu composites from pure Al to pure Cu consolidated at 723K all exceeded 98.5%. The optimum sintering conditions were then determined to sintering temperature of 723 K, uniaxial pressure of 100 MPa, and duration time of 2 h. Al and Cu were mixed homogeneously and well compacted, and no obvious pores were found. The thickness of diffusion layer between Al and Cu was very thin, only about 0.6 μm. The wave impedance values increased almost linearly from 16.98×106to 40.66×106kg/m2·s with increasing Cu content in Al-Cu composite from 0 to 100 vol.%, which was well consistence with the values calculated according to the rule of mixtures. The elastic modulus of different compositions matched well with the theoretical model of Voigt and Reuss. Highly densified Al-Cu composites without intermetallic compounds were successfully prepared using hot-pressure sintering, which was the basis of fabricating Al-Cu system graded density impactors.

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Final Report 02-ERD-033: Rapid Resolidification of Metals using Dynamic Compression

Cited by 4 publications

References 15 publications

Noncontact density measurements of tantalum and rhenium in the liquid and undercooled states

Noncontact density measurements of tantalum and rhenium in the liquid and undercooled states

Homogeneous crystal nucleation in liquid copper under quasi-isentropic compression

Microstructure and Properties of Aluminum-Copper Composites Prepared by Hot-Pressure Sintering

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