Mg-Gd-Zn-Ni-Zr rare-earth magnesium alloy for semisolid forming and preparation method for semisolid blank of semisolid Mg-Gd-Zn-Ni-Zr rare-earth magnesium alloy

Abstract

The invention discloses an Mg-Gd-Zn-Ni-Zr rare-earth magnesium alloy for semisolid forming and a preparation method for a semisolid blank of the semisolid Mg-Gd-Zn-Ni-Zr rare-earth magnesium alloy. The alloy comprises the following components in percentage by weight: 15-21% of Gd, 2.0-3.6% of Zn, 0-0.5% of Ni, 0.3-0.7% of Zr and Mg in balancing amount. The preparation method for the semisolid blank comprises the following steps: taking pure Mg, pure Gd, pure Zn, pure Ni and an Mg-30wt.%Zr intermediate alloy as raw materials, first smelting the raw materials to prepare a master alloy ingot, then performing low-temperature semisolid isothermal heat treatment of the master alloy ingot, and finally performing water quenching to obtain the semisolid blank. The magnesium alloy for semisolid forming, provided by the invention, belongs to an Mg-RE series high-strength magnesium alloy, the semisolid forming temperature of the magnesium alloy is low, the solid-phase content of the magnesium alloy has low susceptibility to temperature variation, and the roundness of obtained solid-phase particles is high. According to the preparation method for the semisolid blank, provided by the invention, the preparation temperature is low, less oxidation and combustion are caused, the process is easy to control, and a semisolid forming technology is appropriate for preparing high-strength and complex-shaped magnesium alloy parts.

Description

technical field [0001] The invention relates to a magnesium alloy and a preparation method thereof, in particular to a Mg-Gd-Zn-Zr magnesium alloy for semi-solid forming and a preparation method of the semi-solid blank. Background technique [0002] Semi-solid metal forming technology has many advantages such as high efficiency, energy saving, near (net) forming production, and high performance of formed parts. It is known as the most promising metal material processing technology in the 21st century, especially the semi-solid forming of magnesium alloys, which can greatly reduce Defects such as oxidation, combustion, porosity, and shrinkage porosity in the production of magnesium alloy parts by ordinary die-casting methods lay the foundation for the wide-scale promotion and application of magnesium alloys. The preparation of high-quality blanks with non-dendritic structure is the premise of semi-solid forming. There are many methods for preparing magnesium alloy semi-solid...

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Problems solved by technology

However, due to the high melting point of Mg in Mg-RE high-strength rare earth magnesium alloys, the temperature for semi-solid isothermal heat treatment to prepare semi-solid billets and the corresponding semi-solid forming temperature is relatively high, often higher than 600 °C ( For example, "Microstructure evolution during reheating of extruded Mg-Gd-Y-Zr alloy into semisolid state" published by Gao Lei, "Transactions of NonferrousMetals Society of China" 2010, Volume 20, pages 1585-1590; Guohua Wu published "Microstructure evolution of semi-solid Mg-10Gd-3Y-0.5Zr alloy during isothermal heat treatment", "Journal of Magnesium and alloys" 2013, Volume 1, pages 39-46), leading to an increase in the risk of magnesium alloy oxidation and combustion, thereby reducing the risk of magnesium alloy finished products Reduced quality, increased energy consumption and production costs for semi-solid forming

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