Method for improving the ductility of high-strength nanophase alloys

Abstract

A method for consolidating nanophase metal powder includes the steps of consolidating the powder by applying pressure to the powder at a first temperature, encompassing the powder with a flowable pressure transmitting medium that is heated to a second temperature that is higher than the first temperature, and compressing the heated medium and thereby further consolidating the powder. The first consolidating step may include encompassing the nanophase metal powder with a flowable pressure transmitting medium that is heated to the first temperature, and compressing the heated medium at the first temperature.

Description

TECHNICAL FIELD [0001] The present invention generally relates to processes for manufacturing metal alloys, and more particularly relates to improving the ductility of nanophase alloys made from metals such as aluminum or iron. BACKGROUND [0002] Solid materials synthesized from particles having a grain size in the nanometer range are the subject of active development due to their unique properties. For example, nanometer-scale crystals have the potential of improving the processing and performance characteristics of ceramics, composite polymers, and inter-metallic materials, along with systems, and media incorporating such materials. Products and materials with nanometer-scale crystallites are formed from nanometer-scale particles in processes that entail the steps of forming the particles of the desired chemistry and size scale, combining the particles, and then densifying the particles. Traditional metallurgical techniques such as casting, hot rolling, isostatic pressing, and powd...

AI Technical Summary

Benefits of technology

The patent describes a method for consolidating nanophase metal powder by applying pressure to the powder at a first temperature, encompassing the powder with a flowable pressure transmitting medium that is heated to a second temperature that is higher than the first temperature, and compressing the heated medium and thereby further consolidating the powder. The technical effect of this method is the improved consolidation of nanophase metal powder, resulting in improved properties such as higher strength and better ductility.

Problems solved by technology

The PPB's are relatively weak and consequently reduce the billet strength and ductility.

The PPB's also cause large scatter in the tensile test results.

However, such a process is typically very parameter sensitive, and results in a material with anisotropic tensile properties.

The above processes are time consuming and are typically conducted using separate and costly forging processes.

Moreover, the numerous processes do relatively little for improving the material ductility, and subject the material to temperatures and strains that adversely affect the material strength.

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