ABSTRACT
Since the discovery of age-hardening, various kinds of high-strength aluminium-based alloys have been produced over the subsequent eight decades. It is known that these aluminium-based alloys have been developed by use of the following strengthening mechanisms: (1) solid solution strengthening, (2) precipitation strengthening, (3) grain size refinement strengthening, (4) dispersion strengthening, (5) work hardening and (6) fibre reinforcement. However, the use of these conventional strengthening mechanisms leads to an upper limit of tensile strength of 500 to 600MPa at room temperature. Consequently, in order to develop a new type of aluminium-based alloys with much higher tensile strength, the use of completely different strengthening mechanisms seems to be essential. More recently, we have carried out systematic studies on the development of high-strength aluminium-based alloys by utilization of nonequilibrium phase effects. In particular, great attention has been paid to nonperiodic structure alloys consisting of amorphous and quasicrystalline phases.
