The combustion synthesis of copper aluminides

Formation and distribution of brittle structures in friction stir welding of aluminium and copper: influence of process parameters

“…Concerning the CuAl 2 phase, previous studies reported that this compound has an enthalpy of formation significantly lower than the Cu 9 Al 4 25 25,26 Effectively, from the Al–Cu equilibrium diagram, it is possible to observe that the formation of this phase results from a peritectic reaction, which occurs at 590°C 3 …”

“…Concerning the CuAl 2 phase, previous studies reported that this compound has an enthalpy of formation significantly lower than the Cu 9 Al 4 . 25,26 Effectively, from the Al-Cu equilibrium diagram, it is possible to observe that the formation of this phase results from a peritectic reaction, which occurs at 590uC. 3,15 However, during FSW, the formation of this compound should also be explained based on a thermomechanically induced solid state diffusion process, since, although its melting temperature is close to the FSW temperatures, no solidification structures such as primary dendrites of Al and CuAl 2 and/or Al-CuAl 2 eutectic structures were detected in the SEM analysis.…”

Synthesis of (U,Zr)C Solid Solutions under Exothermic Conditions

“…At a low external heating rate, the sample spends more time at temperatures for solid diffusion to occur, and substantial amounts of intermediate product phases can form. The formation of internlediate phases have been observed in other exothermic solid reactant systems [Wang et al 1990]. The formation of intermediate products not only reduces the available thermodynamic driving force for subsequent combustion reaction triggered by the presence of liquid [Wang et al.…”

“…The formation of internlediate phases have been observed in other exothermic solid reactant systems [Wang et al 1990]. The formation of intermediate products not only reduces the available thermodynamic driving force for subsequent combustion reaction triggered by the presence of liquid [Wang et al. 1990], but can also form diffusional barriers between reactant atoms.…”

Finite-difference modelling of self-propagating high-temperature synthesis of materials

“…The weak exothermic reactions, such as Si + C ---* SiC and Ti + Ni -+ TiNi lie well within the "No SHS" zone and the "thermal explosion" method must be used to produce a reaction. reactions, Tstar t = 298 K unless indicated Si + C ~ SiC [28] Ti + Ni ~ TiNi [29] 9Cu + 4A1 ~ Cu9A14 [30] 3ZrO2 + 4AI + 3C----~ 3ZrC + 2A1203 [15] Ti + AI---~ TiAI [31] Mo + 2Si ---* MoSi 2 [32] 2Ni + Si --4 Ni2Si [33] Ni + AI ---* NiA1 [34] Ti + C--~ TiC [35] Ti + 2B ~ TiB 2 [36] 3TiO 2 + 4A1 + 3C ---* TiC + 2A1203 [15] ( The effect of preheating on the SHS reaction Ti + AI ~ TiAI can also be seen in Table 3. It has been reported by Yi et al [31] that preheating above 373 K is required to produce a steady SHS reaction.…”