A new approach to the modeling of SHS reactions: Combustion synthesis of transition metal aluminides

Gennari, Silvia; Tamburini, Umberto Anselmi; Maglia, Filippo; Spinolo, G.; Munir, Zuhair A.

doi:10.1016/j.actamat.2006.01.009

Cited by 50 publications

(23 citation statements)

References 28 publications

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“…In accordance with Fourier's law for heat transport, the combustion velocity for diffusion controlled SHS processes can be described from equation (3) [13]: where k is the thermal conductivity, C p is the heat capacity, a 0 is the initial layer thickness of one of the reactants, w is the stoichiometric ratio of the layer of the second reactant, D 0 is the diffusion coefficient pre-exponential, R is the gas constant and E is the diffusion activation energy. The use of a diffusion controlled model to simulate the effect of dilutants on the combustion velocity of NiAl synthesis show good agreement with practical results [14]. As previously discussed, the addition of Al 2 O 3 has little effect on heat capacity whereas the changes in the diffusion coefficient D 0 and thermal conductivity k are considerable.…”

Section: Ignition Processmentioning

confidence: 55%

Combustion synthesis of NiAl/Al2O3 composites by induction heating

et al. 2010

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Section: Ignition Processmentioning

confidence: 55%

Combustion synthesis of NiAl/Al2O3 composites by induction heating

et al. 2010

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“…Once ignited, the SHS reaction releases a large amount of energy in a short period of time. One significant difference between SHS and typical combustion processes is that the reactants and products are confined to the condensed state (4). The SHS process has many potential applications where heat generation is required and oxygen is not available or gaseous products are not desirable.…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulation of the Kinetic Reaction of Nickel and Aluminum Nanoparticles

Henz¹,

Hawa²,

Zachariah³

2010

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Approved for public release; distribution unlimited. ii REPORT DOCUMENTATION PAGEForm Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY) March 20102. REPORT TYPE ARL-TR-5134 SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S) SPONSOR/MONITOR'S REPORT NUMBER(S) DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release; distribution unlimited. SUPPLEMENTARY NOTES ABSTRACTMolecular dynamics simulations are used to simulate the kinetic reaction of nickel (Ni) and aluminum (Al) particles at the nanometer scale. The effect of particle size on reaction time and temperature for separate nanoparticles is considered as a model system for a powder metallurgy system. Coated nanoparticles in the form of Ni-coated Al nanoparticles and Al-coated Ni nanoparticles are also analyzed as a model for nanoparticles embedded within a matrix. The differences in melting temperature and phase change behavior, e.g., the volumetric expansion of Al between Al and Ni is expected to produce differing results for the coated nanoparticle systems. For instance, the volumetric expansion of Al upon melting is expected to produce large tensile stresses and possibly rupture in the Ni shell for Ni-coated Al. Simulation results showed that the sintering time for separate and coated nanoparticles was nearly linearly dependent upon the number of atoms or volume of the sintering nanoparticles. We also found that nanoparticle size and surface energy was an important factor in determining the adiabatic reaction temperature for both systems at nanoparticle sizes of less than 10 nm in diameter. iii SUBJECT TERMS

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“…3(d) [40]) weak beam electron imaging showed high and low dislocation concentrations in alternating bands. The fault band spacing decreases from about lOOnm in unalloyed NiAl [64] to the very fine 10 -50nm bands with alloying additions (Fig. 3(d)) [40].…”

Section: Nano-particles and Nano-bandsmentioning

confidence: 99%

“…The sub-reactions shown below, especially when oscillatory (i.e., dissipative), offers a method of dispersing nano-particles and faulted regions in a manner similar to micro-particle and micro-band formation in lower temperature chemical reactions [7], We also compile evidence from the literature for the sub-reactions and BZ hypothesis from published synchrotron and fine-scale time-lapse XRD studies [24,26,27,32,46,60,61] for explosive micropyretic synthesis of NiAl and other compounds. A compilation of published data [24,25,41,47,[62][63][64][65] and new data on thermal oscillations also points to the BZ hypothesis [31,40,[66][67][68][69][70][71]. Table 1 Variation in the product phases generated from the different processing techniques and initial conditions [10,27,29,[42][43][44][45][46][47].…”

Section: Introductionmentioning

confidence: 99%