Synthesis and Indentation Behavior of Amorphous and Nanocrystalline Phases in Rapidly Quenched Cu–Ga–Mg–Ti and Cu–Al–Mg–Ti Alloys

Abstract

Rapidly solidified ribbons of Cu-Ga-Mg-Ti and Cu-Al-Mg-Ti alloys show the formation of c-brass type phase, which is an approximant of quasicrystals. The Cu-Ga-Mg-Ti alloy displays ordered c-brass structure, whereas Cu-Al-Mg-Ti leads to the formation of amorphous and nanocrystalline disordered bcc c-brass phase.The hardness values of as-synthesized ribbons of Cu-GaMg-Ti and Cu-Al-Mg-Ti alloys are *7.36 and *9.01 GPa, respectively. The high hardness value of the Cu-Al-Mg-Ti alloy can be attributed to the combined effects of amorphous and nanocrystalline phases. The absence of cracks around the indentation up to 100 g of load of this alloy suggests better toughness in comparison with Cu-Ga-Mg-Ti alloy. The formation of shear bands is more prominent in case of Cu-Al-Mg-Ti alloy. The value of yield strength and Meyer exponent of the material has been estimated. It has been found that the indentation parameter seems to be sensitive to structural and microstructural variations.

Glass forming ability, thermal stability and indentation characteristics of Ce 60 Cu 25 Al 15−x Ga x (0 ≤ x ≤ 4) metallic glasses

“…Since Ga and Al are isoelectronic with similar atomic radii, the substitution of Al by Ga does not change the e/a ratio of Ce 60 Cu 25 Al 15 alloy system. Our earlier investigations on the nature of Ga systems in different alloy compositions are also relevant in this connection [24][25][26][27]. The purpose of this work is to understand the compositional dependence of glass forming ability and their mechanical properties in Ce 60 Cu 25 Al 15 − x Ga x alloys.…”

Effect of cooling rate on the crystallization and mechanical behaviour of Zr–Ga–Cu–Ni metallic glass composition

“…It can be seen from the load dependent hardness curves (Fig. 7) that the hardness decreases with increase in the load due to indentation size effect (ISE) [49,50]. Table 3.…”

Structure Analysis of Quasicrystal Approximants by Rotation Electron Diffraction (RED)

“…Since, complex dense intermetallic compounds such as quasicrystal approximants contain heavy elements and thus suffer more from dynamical scattering, it is interesting to see if they can also be solved from RED data. Quasicrystals possess aperiodic long-range order associated with crystallographically forbidden rotational symmetries (5-, 8-, 10-, or 12-fold) and exhibit many outstanding physical properties [7][8][9][10][11][12][13]. Several breakthrough experiments performed by Dan Shechtman in 1982 on rapidly solidified Al-Mn alloys have led to the discovery of quasicrystals.…”

“…It exhibits sharp diffraction peaks with icosahedral symmetry [14]. Quasicrystals exhibit unique physical properties which strongly differ from the properties of metals, insulators, and crystalline or amorphous phases [7][8][9][10][11][12][13][15][16][17][18][19][20][21]. Thus, these materials have the potential to be used in many areas of advanced technology.…”