Thermal Stability of the Structure and Mechanical Properties of Fine-Grained Aluminum Conductor Alloys Al–Mg–Zr–Sc(Yb)
Abstract
The thermal stability of a fine-grained aluminum wire made of Al–Mg–Zr–Sc(Yb) alloys with different zirconium and scandium (ytterbium) contents is studied. Samples are produced by induction casting and subsequent cold working by drawing. The structure and properties of fine-grained the Al–0.6Mg–Zr–Sc alloys are shown to exhibit high thermal stability due to preliminary (before drawing) annealing at 320°C for 2 h, resulting in the precipitation of intermetallic Al3(ScxZr1 – x) particles. A fine-grained homogeneous structure with an average grain size of 2.4–2.8 μm and a microhardness of 405–440 MPa is found to be retained in the Al–0.6Mg–Zr–Sc alloys after prolonged annealing at 400°C for 100 h. A fine-grained magnesium-free Al–0.33Zr–0.16Yb ytterbium alloy has a low hardness and low thermal stability. The average grain size in it after annealing at 400°C for 100 h is 4.1–4.8 μm.