High strength Al metal-matrix microcomposite wire with 20 vol % Nb and ultimate tensile strengths up to 1030 MPa
- Massachusetts Inst. of Tech., Cambridge (United States)
In conventional composite structures a property F can often be related to the properties of the individual components through the rule of mixtures (ROM). Metal-matrix structures in which the second metal B is finely dispersed can have properties that deviate strongly from the ROM. Several binary systems have been extensively investigated, notably Cu-Nb and Ag-Cu. These binary mixtures are typically produced by means of casting or powder metallurgy. The powder metallurgy (PM) route allows the production of a billet without melting, and can prevent the formation of solid solutions. Mechanical deformation to high strains of these casts or PM billets by extrusion and wire drawing produces a very fine filament size of the minority phase. These microcomposites have a filament thickness in the range of 10-200 nm or less. At high [eta] (strain) the ultimate tensile stress (UTS) of the mixtures exceeds the UTS calculated with the rule of mixtures UTS[sub ROM]. For proper UTS[sub ROM] calculations UTS values of the pure constituents that have been strained over a comparable range must be used. In a recent study Spitzig measured a UTS of 1400 MPa for cast Nb deformed to [eta] = 11.5. In the present work a 100% Nb wire using Nb powder, deformed to [eta] = 12.8, had a UTS of 1440 MPa. For cu the authors assumed 495 MPa (1) at [eta] = 11.5. The authors found similar strengthening effects in Al-Nb PM wires. The strengthening is measured in wires in which Al is the majority phase, but also in wires with Nb as the majority phase.
- OSTI ID:
- 6785308
- Journal Information:
- Scripta Metallurgica et Materialia; (United States), Journal Name: Scripta Metallurgica et Materialia; (United States) Vol. 28:8; ISSN SCRMEX; ISSN 0956-716X
- Country of Publication:
- United States
- Language:
- English
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