A die-casting alloy material for a mobile phone middle plate with high yield and high elongation and its preparation method

Abstract

The invention relates to a high-yield and high-elongation die-casting alloy material for a mobile phone middle plate and a preparation method thereof. The alloy includes Si: 2.0wt%-4.0wt%; Mg: 4.5wt%-6.8wt%; Mn: 0.6wt% ‑1.2wt%; Ce: 0.001wt%‑1.0wt%; Cr: 0.001wt%‑0.5wt%; Fe: 0.2wt%‑1.0wt%; Ti: 0.05wt%‑0.25wt%, the remaining impurities are controlled at 1.0 Wt% or less, the balance is Al. Compared with the prior art, the present invention introduces the multi-element strengthening phase Mg by adding the multi-element strengthening phase Mn, Si, Mg, Ce to the aluminum alloy 2 Si, MnAl 6 、CeSi 2 and Al 11 Ce 3 , significantly improve the yield strength and elongation of the material, so that the yield strength of the material can reach 250-280MPa and the elongation can reach 6-12% when the material is thin-walled.

Description

technical field [0001] The invention relates to an aluminum alloy, in particular to a die-casting alloy material for a middle plate of a mobile phone with high yield and high elongation and a preparation method thereof. Background technique [0002] The mobile phone mid-board refers to the substrate inside the high-end smartphone, which is mainly used to support the internal circuit board of the mobile phone, and its thickness is generally thin, about 0.5mm. These performances of the mobile phone middle board require the material to have high strength to ensure the strength required for it to support the circuit board; with the increase of the mobile phone screen, the size of the mobile phone middle board also increases, and its structure is simpler, The material is required to have a high elongation; the material is required to have excellent forming properties, so that it can be easily punched and bent at a small angle to ensure that it does not crack when forming; the mat...

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Problems solved by technology

[0006] Patent application 2019101896620 claims a high thermal conductivity and high yield die-casting alloy material for mobile phone mid-plate and its preparation method. A certain Zn element is added to the alloy material formula for the purpose of forming MgZn in the alloy material 2 Strengthening phase, although it improves the yield performance of the alloy to a certain extent, but (Mg, Cu) Zn 2 The phase is very brittle and incoherent with the matrix, and it is easy to peel off the interface with the matrix, and it is easy to generate interstitial dislocations under low stress, forming pores that become shortcuts for crack propagation and act as crack sources. When the strain is concentrated in Grain boundary, it is easy to produce intergranular fracture characteristics, thus strongly reducing the fracture toughness of the alloy

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