High-strength and heat-resistant aluminum alloy wire and preparation method thereof

Abstract

The invention discloses a high-strength and heat-resistant aluminum alloy wire and a preparation method thereof. The aluminum alloy wire comprises the composition by the mass percentage: 0.6-1.2% of Mg, 0.4-0.8% of Si, 3.0-7.0% of W, and the balance Al. The preparation method of the aluminum alloy wire comprises the following steps: preparing an aluminum alloy liquid, atomizing the aluminum alloy liquid into a powder, screening the aluminum alloy powder, mixing a tungsten powder with the particle size of not more than 3 microns with the aluminum alloy powder, carrying out cold isostatic pressing on the mixed powder into a prefabricated blank, carrying out vacuum degassing, heating, hot-extruding into an aluminum alloy round rod, drawing into an aluminum alloy wire, and carrying out solid solution and aging treatment to obtain the high-strength and heat-resistant aluminum alloy wire. Tungsten is uniformly added into the aluminum alloy wire by adopting a powder hot extrusion method, the strength of the aluminum alloy wire is strengthened, the aluminum alloy wire has excellent room-temperature tensile mechanical properties, electrical conductivity and heat resistance, the room-temperature tensile strength is more than 320 MPa, the elongation rate is more than 9%, the electrical conductivity is more than 56%IACS, and after heat preservation for 1 h at the temperature of 250 DEG C, the tensile strength is more than 290 MPa and the tensile strength survival rate is more than 91%.

Description

Technical field [0001] The invention belongs to the field of aluminum alloy wire preparation, and specifically relates to a high-strength heat-resistant aluminum alloy wire and a preparation method thereof. Background technique [0002] With the rapid development of my country's national economy, the construction of the power industry is advancing by leaps and bounds. The construction of transmission lines is developing in the direction of long distances, large spans, ultra-high voltages, and large capacities. Aluminum alloys are used for overhead transmission lines and ultra-high voltage distribution station tubular busbars. Materials also put forward higher requirements, not only requiring high strength and good electrical conductivity, but also requiring better heat resistance. The heat resistance of heat-resistant aluminum alloy wire is usually characterized by measuring its residual tensile strength and the residual rate of tensile strength after holding it at a high temperat...

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Problems solved by technology

[0007] From the analysis of literature, it can be seen that the existing technology mainly improves the heat resistance of Al-Mg-Si alloy wires by adding elements such as Zr, Sc, B, La, etc., and the room temperature tensile strength of aluminum alloy wires is lower than 260MPa. The tensile strength after annealing at 250°C for 1 hour is lower than 230MPa, and the residual rate is lower than 90%, which is difficult to meet the manufacturing requirements of large-span, ultra-high voltage, large-capacity transmission wires and tubular busbars

[0008] Tungsten is a silver-white, lustrous, body-centered cubic metal with high melting point and stable chemical properties. Adding tungsten to aluminum alloy and utilizing the high temperature resistance of tungsten is expected to develop a new type of high-strength Heat-resistant aluminum alloy wire, but the melting point and density of tungsten and aluminum alloy are very different. The melting point of tungsten is 3422°C and the density is 19.35g / cm 3 , the melting point of aluminum alloy is usually 580~650℃, and the density is 2.7~2.9g / cm 3 , therefore, the conventional aluminum alloy high-temperature melting and casting method cannot uniformly add tungsten into the aluminum alloy

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