Hello Everyone,

 

Considering Eyal’s and Dawn’s emails, I am emailing to see if people have given any more thought to the dynamic phase transition proposals.

 

IAEC has interest in following: Tin, Si/Ge, Ti, CaF2

Sandia has interest in Co and CaF2

 

Are there other materials of interest? According to Eyal, Si/Ge is probably out for now until we can get more reliable samples.

 

For reference, I’ve included a phase digram of CaF2 from Carzola and Errandonea (Phys. Rev. Lett. 113, 235902, 2014). There is another phase diagram in J. R. Nelson PRB 85, 054118, 2017. I have attached both papers as well.  The alpha-gamma transition is easy to obtain using either Sandia or IAEC gun systems. One topic of interest might be to try to reach the delta phase using IAEC’s preheat capabilities and by shock compressing porous CaF2 samples (pressed powders). We could try to develop shock-ramp experiments to explore the gamma-delta phase boundary.

 

We also have interest in doing shock-ramp experiments on single crystal CaF2 near the incompressibility region on the Hugoniot (~100 GPa). We could submit a joint proposal for Z’s fundamental science program looking at shock-ramped CaF2. Furthermore, doing DFT and possibly DAC work on the phase diagram above 30 GPa would be of great value.

 

Does IAEC have a specific region of interest for CaF2? Sound speed measurements on the alpha-gamma transition?

 

I’ve also included a paper on our work on Tin where we did use the shock-ramp platform.  This paper should provide some perspective as to what Z can do with the shock-ramp and show what we have already completed in our work on Tin.

 

 

 

 

Seth

 

—————————————————————————

Seth Root

Sandia National Laboratories

Office: 505-284-1749

Mobile: 505-328-6322

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From: Eyal Yahel <eyalyahel@gmail.com>
Date: Saturday, August 19, 2017 at 1:33 PM
To: Dawn Flicker <dgflick@sandia.gov>
Cc: "Sarrao, John Louis (LANL)" <sarrao@lanl.gov>, "Fox, Glenn A." <fox7@llnl.gov>, Elazar Sarid <elazarsa@soreq.gov.il>, Seth Root <sroot@sandia.gov>, "Specht, Paul Elliott" <pespech@sandia.gov>, "Mattsson, R" <trmatts@sandia.gov>, "Benage, John F" <jfbenag@sandia.gov>, "Molina, Vanessa M" <vmmolin@sandia.gov>, Melchior Aviva <avimel@gmail.com>, Avi Ravid <aviravid@soreq.gov.il>, "arnony@nrcn.gov.il" <arnony@nrcn.gov.il>, "vitalyP@nrcn.gov.il" <vitalyP@nrcn.gov.il>
Subject: Re: [EXTERNAL] NNSA/IAEC Material Science Topic

 

Dear all, 

 

Sorry for being slow in our reply.

 

I agree with Dawn regarding the workshop in October, and I suggest to check its relevance towards the beginning of 2018.

 

Below please find some comments Arnon and Vitaly drafted.

 

In regard to possible AM materials for both AM proposals:

1. NRCN cannot provide AM stainless steel or pure titanium samples at timescales relevant for this study. i.e. We can provide specimens of Ti64 produced by EBM and SLM and AI10SiMg produced by SLM.

2. Nevertheless, we interested in studies of other AM materials (such as stainless steel 304L), but to carry out research plan, the specimens should be supplied by the NNSA.

For the first proposal on AM - The dynamic evaluation of AM materials is a part of a broader
proposal on characterization of AM materials which is currently concentrated on Ti64. 

Therefore we think that the dynamic part of this proposal should also be done
on the Ti64 alloy, at least at the first stage.

For the second proposal (Effect of microstructure - pores, gas bubbles, inclusions- on
dynamic behavior of AM materials) - The only material (except Ti64) available now (to NRCN)
to begin with is AI10SiMg. This aluminum alloy can be manufactured using SLM method with
powder bed. The resulting porosity is of about 0.5-1.5%, while pores' of 1-10 microns in size
are actually argon bubbles. The subsequent HIP post-processing can reduce the pores' size,
while the argon pressure will increase. By varying the HIP parameters one can control the
pores size/argon pressure to study the effect of the latter on the dynamic
behavior of the alloy and particularly on the spall strength.

Dynamic phase transitions

1.        In addition to the potential materials Dawn listed, the discussion also included Sn,
with an interest mostly on its melting along the Hugoniot at about 70 GPa (although
it does also have a solid-solid transition at a low pressure). It seems that this is
relevant to several studies presented during the conference at St. Louis. NRCN and SNRC
suggested to apply sound velocity techniques to better investigate the transition.
Our facilities will allow us to perform experiments up to about the melting point,
and we suggest that these experiments should be complemented with experiments
at higher pressures by using NNSA's guns with higher impact velocities or other high
pressure facilities. In addition, we suggest to perform experiments with elevated
initial temperature which we can perform currently on our single stage gas gun
system. NRCN can also contribute Ab-Initio DFT calculations for all relevant phases
and calibration of equation of state. It will be valuable to validate such against the
experiments as well as modeling by other parties.

2.        Si and Ge are still of interest to NRCN, but because of the higher complexity- both of
the experimental techniques and of the physical processes involved, it is suggested
that this proposal will re-evaluated and incorporated into the collaboration at a later stage.

3.        Of the other materials suggested, IAEC is interested in studies of pure Ti and CaF, but
further work is needed in order to write a detailed proposal.

There is a small correction to the list names of the people present in the meeting.

Here is the correct list for the Israeli side:

SNRC: Avi Ravid, Beni Glam; IAEC: Eli Gudinetsky; NRCN: Vitaly Paris, Arnon Yosef-Hai

Dynamic loading capabilities of IAEC labs:

1.       Gas gun (NRCN): 25-mm bore gas gun, velocity capability is up to 1 km/sec, VISAR
diagnostics.

Current efforts focus on setup impact experiments with pre-heating targets to temperatures
up to 1000°C.

2.       SHPB (NRCN): 0.5’’ and 1" Hopkinson bar systems; capabilities to test standard
compressive samples and shear samples; strain rates are 10³-10⁴ sec^-1,

3. Powder gun (SNRC):40-mm bore, velocities up to 2.5 km/sec, VISAR diagnostics

Calculations from first principles capabilities (NRCN):

Calculations of the lattice parameters, lattice stability and phonon dispersion curves of solid
phases of metals are done within density functional theory (DFT). Results of DFT
calculations are employed to estimate the entropy and free energies of the phases (e.g., 
alpha and omega phases of Ti).

First principles calculations of representative semiconductor (Si) and representative metal
(Ti) performed using density-functional perturbation theory. 

EOS study of tin from first principles using DFT is planned.

 

Dawn - 

 

We clearly have 2-3 proposals. 

I think the next step is to have a plan for each and organize it in a proposal to be submitted to the Chief scientists.

 

Eyal 

 

 

 

On Tue, Aug 8, 2017 at 7:50 PM, Flicker, Dawn G <dgflick@sandia.gov> wrote:

Eyal –

    It doesn’t look like it would be practical to have the materials workshop at Argonne this time.

Sandia could host, but we would need have pretty firm plans within the next few weeks. We will

start looking at possible arrangements for that week. 

 

I haven’t seen any responses to my email of 7/25.  It makes the most sense to have a workshop if we think there are some good areas to explore in depth.

 

Thanks

Dawn

 

From: Eyal Yahel [mailto:eyalyahel@gmail.com]
Sent: Sunday, August 06, 2017 2:02 PM
To: Flicker, Dawn G <dgflick@sandia.gov>; Sarrao, John Louis (LANL) <sarrao@lanl.gov>; Fox, Glenn A. <fox7@llnl.gov>
Cc: Elazar Sarid <elazarsa@soreq.gov.il>
Subject: [EXTERNAL] NNSA/IAEC Material Science Topic

 

Dear all, 

 

I wish to thank Dawn for organizing the meeting in St. Louis.

In the next couple of days we will update on the action items Dawn drafted. 

 

In the meantime, I would like to check on Dawn's suggestion to have a small workshop at Argonne (APS/DCS) to:

 

1. To get acquainted with the facility (Israelis)

2. To have extended presentations and discussions on the proposals   

3. Use it as mid year meeting on dynamical experiments.

 

I suggest to take advantage of the APS in Wisconsin (some of the relevant IL PI's will attend) and couple the workshop to the week that follows it, namely, Monday the 30.10.17

Would that work for the US PI's? 

 

Eyal

 

--

Eyal Yahel, Ph.D.
Chief Scientist NRCN
P.O.Box 9001 Beer-Sheva,
Israel, 84190