Table 3 Common precipitates in Al–Li alloys and their crystal structure information [3, 102, 103]
From: Hot Extrusion Processing of Al–Li Alloy Profiles and Related Issues: A Review
Precipitates | Lattice types | Lattice constants (nm) | Orientation relationships | Characteristics |
|---|---|---|---|---|
\({\theta^{\prime\prime}}\) (Al2Cu) | Tetragonal | a = 0.404, c = 0.78 | \(\left( {100} \right)_{\text{Al}} //\left( {100} \right)_{{{\theta^{\prime\prime}}}}\) \(\left[ {001} \right]_{\text{Al}} //\left[ {001} \right]_{{{\theta^{\prime\prime}}}}\) | Coherent, plate-like |
\({\theta^{\prime}}\) (Al2Cu) | Tetragonal | a = 0.404, c = 0.58 | \(\left( {100} \right)_{\text{Al}} //\left( {100} \right)_{{{\theta^{\prime}}}}\) \(\left[ {001} \right]_{\text{Al}} //\left[ {001} \right]_{{{\theta^{\prime}}}}\) | Semi-coherent, lath-like |
\({\delta^{\prime}}\) (Al3Li) | Cubic (L12) | a = 0.401 | Cube-Cube | Coherent, ordered, spherical and metastable |
\(\updelta\) (AlLi) | Cubic (B32) | a = 0.637 | \(\left( {100} \right)_{\text{Al}} //\left( {100} \right)_{\updelta}\) \(\left( {111} \right)_{\text{Al}} //\left( {011} \right)_{\updelta}\) | Incoherent, spherical |
\({\text{T}}_{1}\) (Al2CuLi) | Hexagonal | a = 0.497, c = 0.935 | \(\left( {111} \right)_{\text{Al}} //\left( {0001} \right)_{{{\text{T}}_{1} }}\) \(\left[ {211} \right]_{\text{Al}} //[1120]_{{{\text{T}}_{1} }}\) \([110]_{\text{Al}} //[1010]_{{{\text{T}}_{1} }}\) | Semi-coherent, plate-like |
\({\text{T}}_{\text{B}}\) (Al7.5Cu4Li) | Cubic (CaF2) | a = 0.583 | \(\left( {110} \right)_{\text{Al}} //\left( {100} \right)_{{{\text{T}}_{\text{B}} }}\) \(\left( {001} \right)_{\text{Al}} //\left( {001} \right)_{{{\text{T}}_{\text{B}} }}\) | Lath-like |
\({\text{T}}_{2}\) (Al6CuLi3) | Cubic (Uncertainty) | a = 1.391 | – | Icosahedral symmetry |
\({\text{S}}^{\prime}/{\text{S}}\) (Al2CuMg) | Orthorhombic | a = 0.401, b = 0.925;c = 0.715 | \(\left( {100} \right)_{\text{Al}} //\left( {100} \right)_{\text{S}^{\prime}}\) \(\left[ {021} \right]_{\text{Al}} //\left[ {010} \right]_{\text{S}^{\prime}}\) \([012]_{\text{Al}} //[001]_{\text{S}^{\prime}}\) | Semi-coherent, rod or plate-like |
\({\beta^{\prime}}\) (Al3Zr) | Cubic (L12) | a = 0.405 | Cube-Cube | Coherent, ordered, spherical and dispersed |
\(\varOmega\) (Al2Cu) | Orthorhombic | a = 0.496, b = 0.856, c = 0.848 | \(\left( {211} \right)_{\text{Al}} //\left( {100} \right)_{\varOmega }\) \(\left( {110} \right)_{\text{Al}} //\left( {010} \right)_{\varOmega }\) \(\left( {111} \right)_{\text{Al}} //\left( {001} \right)_{\varOmega }\) | Thin plate-like |
\(\upsigma\) (Al5Cu6Mg2) | Cubic | a = 0.827 | – | Incoherent, square block |