Morphology and thermal characteristics of nano-sized Pb–Sn inclusions in Al

Abstract

Nanoembedded aluminum alloys with bimetallic dispersoids of Sn and Pb of compositions Sn 82 -Pb 18 , Sn 64 -Pb 36 , and Sn 54 -Pb 46 were synthesized by rapid solidification. The two phases, face-centered-cubic Pb and tetragonal Sn solid-solution, coexist in all the particles. The crystallographic relation between the two phases and the matrix depends upon the solidification pathways adopted by the particles. For Al-(Sn 82 -Pb 18 ), we report a new orientation relation given by [011]Al//[010]Sn and (011)A1//(101)Sn. Pb exhibits a cube-on-cube orientation with Al in few particles, while in others no orientation relationship could be observed. In contrast, Pb in Sn 64 -Pb 36 and Sn 54 -Pb 46 particles always exhibits cube-on-cube orientation with the matrix. Sn does not show any orientation relationship with Al or Pb in these cases. Differential scanning calorimetry studies revealed melting at eutectic temperature for all compositions, although solidification pathways are different. Attempts were made to correlate these with the melting and heterogeneous nucleation characteristics.

Formation and Stability of Pb-Sn Embedded Multiphase Alloy Nanoparticles via Mechanical Alloying

“…The OR is quite different from what has been observed in the melt-spun samples as well as ion-implanted specimen of Pb and Sn nanoparticles embedded in Al matrix. [5][6][7][8][9][10][11] In fact, the observed OR is distinctly different from that of the reported individual Pb and Sn nanoparticles embedded in Al. [24][25][26] Thus, it is clear that MA leads to the formation of distinctly different interface between the phases in the nanoparticles and the matrix.…”

“…), various types of multiphase nanoalloy inclusions were prepared by rapid solidification processing (RSP) as well as ion implantation routes. [5][6][7][8][9][10][11][12][13] These studies conclusively reveal the role of the interface between the phases of the nanoparticles and the matrix, in governing the thermal stability and the phase transformation of the nanoinclusions. [7] Earlier studies also indicate that nanoinclusions prepared by RSP, especially melt spinning, exhibit regular shapes and proper orientation relationship (OR) with the matrix.…”

Two‐Phase Equilibrium in Binary Alloy Nano Particles

“…(5)- (8). For solidliquid coexistence one obtains a set of convex free energy curvesg SL (x, x L ,T ) parametrized by the solute fraction x L in the liquid, as illustrated by the example in Fig.…”

“…However, in the recent past a small, but increasing number of studies has been concerned with the phase equilibrium in binary alloy nanoparticles. Particles, typically of an alloy with a simple eutectic phase diagram and embedded in an inert matrix, can be prepared by vacuum deposition [6], ion implantation [7], and by melt spinning [8]. A qualitative difference to elemental particles resides in presence of the internal interface between the phases coexisting within the alloy particle.…”

Positron annihilation and tribological studies of nano-embedded Al alloys

“…This process allows to produce the microand nano-scaled dispersoids in the alloys. Bhattacharya et al [3][4][5][6] established the good tribological properties under mild wear condition of the nano-embedded Al alloys obtained in such a process. The effect of particle's size on the tribological properties is most interesting.…”