Laser additive manufacturing high-strength heat-resistant rare earth aluminum alloy and preparation method thereof

Abstract

The invention provides a laser additive manufacturing high-strength heat-resistant rare earth aluminum alloy and a preparation method thereof. The preparation method comprises the following steps: an aluminum ingot is heated and molten into molten aluminum; required elements are added into the molten aluminum to form alloy liquid, specifically, the alloy liquid comprises, by mass: 1.00%-10.00% of Ce, 0.05%-2.00% of Mg, 0.10%-0.50% of Zr, 0.10%-7.50% of Y, 0.05%-0.50% of Fe, 0.10%-2.00% of Si, and the balance Fe; the alloy liquid is guided out through a flow guide pipe, the alloy liquid is impacted through air flow to form particles, and the particles are solidified into spherical alloy powder; and the spherical alloy powder is rapidly molten, solidified and formed through selective laser melting to obtain the high-strength heat-resistant rare earth aluminum alloy. The high-strength heat-resistant rare earth aluminum alloy has a nanoscale eutectic three-dimensional network skeleton structure, is high in density, has excellent room-temperature and high-temperature mechanical properties, and is relatively low in density.

Description

technical field [0001] The invention relates to the technical field of heat-resistant aluminum alloy materials, in particular to a laser additive manufacturing high-strength heat-resistant rare earth aluminum alloy and a preparation method thereof. Background technique [0002] Heat-resistant aluminum alloy has the advantages of high specific strength, low density, and good oxidation resistance, and has been widely used in aerospace, automobile, ship, weapon and other industries. However, at present, the high-temperature performance of heat-resistant aluminum alloys is close to the limit state. When the working temperature exceeds 200 °C, its mechanical properties will be significantly reduced, which makes it difficult to meet the demand for operating temperature and poses a greater safety hazard. Therefore, the development of new heat-resistant aluminum alloys with excellent room temperature performance, good oxidation resistance and fatigue resistance, and good heat resist...

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Problems solved by technology

However, its preparation needs to go through processes such as homogenization treatment, hot rolling, annealing, cold rolling, and cryogenic deformation. The cycle is long, the processing process is complicated and difficult to control; 1. The price of Ag elements is expensive, which increases the production cost. In addition, these elements are dense, and compound addition is not conducive to the development of lightweight; the patent does not disclose the high-temperature performance of its alloys, and has no reference and guiding significance for the service range above 400 °C

The Chinese patent application number 202010356881.6 discloses an Al-RE-Y-Mg alloy and its preparation method, and discloses a high-strength heat-resistant die-casting / high thermal conductivity and corrosion-resistant Al-RE suitable for pressure / gravity casting -Y-Mg alloy, its room temperature strength is lower than 260MPa, and its high-temperature strength at 250°C is lower than 150MPa, which is not conducive to long-term high-temperature service; and the pressure / gravity casting method has a slow solidification speed, which is prone to defects such as segregation and shrinkage porosity, and poor quality stability , affecting its performance

[0004] Traditional processing techniques mainly improve material strength by refining grains, adding second phases, or increasing dislocations. The heat-resistant aluminum alloys currently reported are based on the precipitation strengthening mechanism, and the strengthening effect comes from the dispersion of the L12 structure formed after heat treatment. Strengthening phase, but due to the limitation of grain size effect, the strengthening effect is not obvious

For example, the mechanical properties of Al-Si alloys are not high, and the combined addition of Sc and Zr will greatly increase the cost, which is not conducive to application and promotion.

Aluminum matrix composites have excellent properties such as high strength and high modulus, but their density is low, the reinforcement phase is dispersed unevenly, and there are often certain defects at the interface between the reinforcement phase and the aluminum matrix, and microcracks occur during use. fail

Al-Zn series high-strength aluminum alloys are prone to hot cracks during solidification, while Al-Ni and Al-Cu series alloys have high density, which is not conducive to lightweight development

Later deformation and heat treatment can improve the strength of the material, but when the working temperature rises, the grains gradually grow and coarsen as the temperature rises, and the strength of the material drops sharply

Moreover, these means have long processing cycles, high energy consumption, and complicated processes.

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