Mechanical Properties of Partially Crystallized Aluminum Based Metallic Glasses

摘要

It is well documented that metallic glasses possess high strength combined withgood bending ductility. The fracture tensile strength of a metallic glass is usually much higher than that of its crystalline state with the same chemical composition. Most metallic glasses lose their high fracture tensile strength and ductility upon crystallization, although there are reports that some metallic glasses still exhibit high fracture strengths and adequate ductility after partial crystallization by quenching or isothermal annealing near their glass transition temperature. Such a sudden loss of ductility and strength is a severe disadvantage of metallic glasses as engineering materials; the retention of these properties after partial crystallization would obviously be very attractive. The present effort is concerned with these properties in the recently discovered group of aluminum metallic glasses containing up to 90% aluminum. The tensile fracture strengths of aluminum metallic glasses are about twice that of the best commercial aluminum alloys and can be of significant importance in obtaining high-strength, low-density engineering materials. This paper focuses on the mechanical behaviors of AlFeGd metallic glasses which are partially crystallized by either quenching or isothermal annealing just below the crystallization temperature as determined by differential scanning calorimetry.