Formation of L1₂modified Al_2.5Cu_0.5Ti phase by heat treatment of spark-plasma-sintered Cu/Al₃Ti specimens

Abstract

In our previous studies, the influence of L1 2 modified Al 2.5 Cu 0.5 Ti and Al 2.7 Fe 0.3 Ti particles on the grain refining performance of an Al cast was studied. It has been shown that the L1 2 modified intermetallic compound particles act as heterogeneous nucleation sites of α-Al solidification. Since nuclei are formed on the surface of the heterogeneous nucleation site particles, only the surface region of the Al 3 Ti particles must be modified into an L1 2 structure. In this study, therefore, the formation of the Al 2.5 Cu 0.5 Ti phase by the reaction between Al 3 Ti and Cu is studied. For this purpose, Cu/Al 3 Ti diffusion couple specimens and specimens of Al 3 Ti particles dispersed in a Cu matrix are fabricated by a spark plasma sintering (SPS) method, and the reaction between Cu and Al 3 Ti during heat treatment of these specimens is studied. It is found that the L1 2 modified Al 2.5 Cu 0.

Thermal Stability of L12‐Modified Al2.5Cu0.5Ti Particles in Al Matrix

“…It is known that grain boundaries and dislocation provide extra diffusion channels. [ 22 ] If grain boundary diffusion is significant, then that can explain the faster decomposition of the gas‐atomized Al 2.5 Cu 0.5 Ti particles as compared with crushed Al 2.5 Cu 0.5 Ti particles in the Al matrix.…”

“…It is known that grain boundaries and dislocation provide extra diffusion channels. [22] If grain boundary diffusion is significant, then that can explain the faster decomposition of the gas-atomized Al 2.5 Cu 0.5 Ti particles as compared with crushed Al 2.5 Cu 0.5 Ti particles in the Al matrix. The microstructures of Al-10 vol%(Al 2.5 Cu 0.5 Ti) specimen fabricated by SPS and heat treated at 750 °C for 3, 5, and 10 min are shown in Figure 6a-c, respectively.…”

Review, Role of L12 Modified (Al1−xMex)3Ti Intermetallic Compounds on Heterogeneous Nucleation of Alpha Aluminum Grains

“…An L1 2 modified Al 2.5 Cu 0.5 Ti intermetallic compound can be formed at the Cu/Al 3 Ti interface in the Cu/Al 3 Ti diffusion couple specimen heated at elevated temperature as shown in Fig. 2 [12]. Therefore, it is expected that these intermetallic compounds show good grain refining performance.…”

“…Micrographs showing the interface in the Cu/Al 3 Ti diffusion couple specimen heated at 600 o C for 4 h[12].…”

Fabrication of grain refiners with a high volume fraction of Al2.7Fe0.3Ti heterogeneous nucleation site particles by spark plasma sintering

“…In our previous studies, [14][15][16][17] it has been shown that L1 2 modified (Al 1−x Me x ) 3 Ti intermetallic compounds [18][19][20][21] show good grain refining performance, although L1 2 modified (Al 1−x Me x ) 3 Ti intermetallic compounds cannot coexist with the Al matrix in an equilibrium state. Al-10 vol%Al 2.7 Fe 0.3 Ti and Al-10 vol%Al 2.7 Ni 0.3 Ti refiners with M values of 2.50 × 10 −3 and 1.93 × 10 −3 , respectively, are successfully fabricated by spark plasma sintering (SPS).…”