Untitled

The Effectiveness of Al-Si Coatings for Preventing Interfacial Reaction in Al-Mg Dissimilar Metal Welding

“…[20] Secondly, pure Al and Si form a eutectic system in which no intermetallic phases exist and the solubility of Si in Al is low (maximum 1.5 wt pct) [25] ; as a result, excessive Si is present in the Al matrix as elemental particles. Given that Al diffusivity in Si is substantially lower than in Mg (D mg~1 0 À16 m 2 /s [26] vs D Si~1 0 À9 to 10 À11 m 2 /s [27] at the peak welding temperatures typically seen in FSSW of Al to Mg at [673 K (400°C)], the Si phase can also function as a discontinuous diffusion barrier and retard Al-Mg inter-diffusion. In addition, Al-Si alloys have good ductility, which is essential for maintaining a continuous interlayer during FSSW and silicon is widely used in Al alloys and can be added in considerable concentrations by casting, which is convenient for manufacturing a coating material.…”

Discontinuous and continuous precipitation in magnesium–aluminium type alloys

“…Recently, investigations concerning precipitation processes in Mg-Al alloys have been reported [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. In most of them, however, discontinuous and continuous precipitation were analysed separately, whereas these two types of precipitates can occur simultaneously and compete in an intricate manner because they nucleate and grow at different rates and with different mechanisms.…”

Interface microstructure and diffusion kinetics in diffusion bonded Mg/Al joint

“…The slopes were the diffusion activation energy Q of Mg and Al in every intermetallic layer, shown in Table 2. The diffusion activation energy Q of Mg and Al in the Mg/Al interfacial transition zone was less than that in Al and Mg (Q=1.13×10 5 J/mol and Q=1.44× 10 5 J/mol, respectively) [10,11]. And the diffusion activation energy, the Q value decreased with increasing the atom percentage in every layer.…”