CN102304656A

CN102304656A - Rare earth heat resistant magnesium alloy with high corrosion resistance

Info

Publication number: CN102304656A
Application number: CN 201110257173
Authority: CN
Inventors: 吴落义
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-09-02
Filing date: 2011-09-02
Publication date: 2012-01-04

Abstract

The invention provides heat-resistant magnesium alloy with rare earth elements Nd and Gd. The alloy has good corrosion resistance and high temperature (200 DEG C) mechanical properties. The alloy mainly comprises the following components: 1-2% of Gd, 2-3% of Nd, 0.5-1.0% of Zn, 0.5% of Zr and the balance of Mg. Harmful elements are controlled as follows: the content of Si is not greater than 0.01%, the content of Cu is not greater than 0.008%, the content of Ni is not greater than 0.001%, the content of Fe is not greater than 0.004% and the content of Al is not greater than 0.003%. The alloy is the alloy which can be strengthened through aging; and the T6 process is adopted to perform heat treatment on the alloy so as to ensure that the alloy can have the expected performance. Solution treatment is performed on the alloy at 500-520 DEG C for 8-12 hours, then the treated alloy is quenched in hot water at 70 DEG C and finally the quenched alloy is placed in an aging treatment furnace at 180-250 DEG C to keep the temperature and ensure that the aging performance of the alloy reaches the peak value.

Description

Heat Resistant Rare Earth-magnesium Alloy with high anti-corrosion

Technical field

The present invention relates to have high anticorrosion stress-resistant property and stable on heating magnesium-rare earth.

Background technology

Magnesiumalloy is the minimum structural metallic materials of present known density.Because the requirement of energy-saving and emission-reduction, the lightweight of the vehicles are emphasis of paying close attention to now, make such as the employing heat resistance magnesium alloys such as transmission case of automobile, can reduce the deadweight of automobile, thereby improve the fuel efficiency of automobile.In addition, aspect electronic industry, the shell of widely used various projector requires to have certain solidity to corrosion and thermotolerance, also to the demands for higher performance of magnesiumalloy.

This type alloy that uses now mainly is the ZE41 cast magnesium alloys, zinc that its main alloying constituent is 4.0 % and the rare earth of 1.0 %.Zn is a kind of element that can improve intensity.But excessive interpolation Zn can reduce the resistance toheat and the castability of alloy.The adding of REE helps improving the high temperature creep property of alloy, but has increased the cost of alloy.ZE41 on overall does not possess the effect of ageing strengthening basically, and its use temperature is the highest must not be above 150 ℃.

Summary of the invention

The present invention will prepare a kind of magnesiumalloy; This alloy can pass through the ageing strengthening of proper heat treatment technology; Have advantages of good casting and corrosion resisting property; When high temperature (200 ℃), have higher yield strength and creep property, can substitute the use of ZE41 at transport facility, Flight Vehicle Design, aerospace field.

1. added rare earth element nd and Gd in this alloy, its content is Gd:1 ~ 2%, Nd:2 ~ 3%.For the over-all properties that improves alloy has added a spot of Zn, its content is 0.5 ~ 1.0%, in addition adds Zr about 0.5% to reach the purpose of crystal grain thinning.Other compositions of magnesiumalloy are Mg and a spot of impurity element.

2. the content of impurity element: Si must not be higher than 0.01%, and Cu must not be higher than 0.008%, and Ni must not be higher than 0.001%, and Fe is not higher than 0.004%, and Al is not higher than 0.003%.Especially to control the content of Fe and Al in the alloy.

3. for to make alloy reach the performance of expection, designed proper heat treatment technology:, in～70 ℃ of hot water, quench subsequently 500～520 ℃ of solution treatment 8～12 hours; Timeliness is to peak value in 180～250 ℃ aging oven.

The control of principle that alloying element is chosen and harmful element content:

Zn

The maximum solid solution degree of zinc in magnesium is 6.2%, is a kind of very effective and alloy element, has the dual function of solution strengthening and ageing strengthening.The also same Zr of Zn, rare earth combine, and form the higher precipitation strength magnesiumalloy of intensity.In addition, Zn also can alleviate the corrosive nature that causes because of Fe, Ni existence.

Zr

The solubleness of zirconium in magnesium is very little, under peritectic temperature, is merely 0.58%, has very strong grain refining effect.The lattice parameter of Zr and magnesium are very approaching, in process of setting, form rich zirconium solid phase particles earlier and will heterogeneous nucleation site be provided for magnesium crystal grain.Zr adds to and serves as grain-refining agent in the alloy.

Gd and Nd

Gadolinium and neodymium all are REEs, and rare earth is the most effectively one of alloying element of magnesiumalloy.REE atomic diffusion ability, both can improve magnesiumalloy Tc with slow down at crystallisation process, can separate out highly stable disperse phase particle again, thereby improve the hot strength and the creep resistance of magnesiumalloy greatly.In magnesiumalloy, add two kinds of REEs of Gd and Nd simultaneously, the reasonable effect between REE can reduce the solid solubility of rare earth in magnesium, and the deposition that influences supersaturated solid solution separates out kinetics, helps improving the volume(tric)fraction of precipitation strength phase.This narrows down for the adding of REE makes the alloy graining temperature range, and can alleviate weld cracking and the compactness that improves foundry goods.

Cu

Copper is the element that influences the alloy corrosion stability, contains a spot of copper and can reduce corrosion resistance of alloy significantly.

Fe and Ni

Iron, nickel also are the elements that influences the alloy corrosion stability, in time the Fe of denier, the corrosion stability that Ni also can reduce alloy greatly.

Thermal treatment process:

This alloy is can be through the suitable high-strength magnesium alloy that gets the reinforcement of thermal treatment process artificial aging, and thermal treatment process is the critical process of alloy preparation.In order to make alloy reach the performance of expection, must carry out suitable thermal treatment to foundry goods or component with reference to the T6 thermal treatment process.

Alloy according to composition preparation provided by the invention has castability preferably, adopts various common castmethods, can the satisfactory heat resistance magnesium alloy kind of obtained performance such as die casting, die casting, gravitational casting etc.

The cast article that makes according to the present invention can be used for manyly requiring in light weightly, and intensity is high, and high-temperature behavior is good, component that solidity to corrosion is good and product.Satisfy in auto parts, aircraft component and the various handheld device of above-mentioned characteristic at needs, this alloy kind can substitute early stage ZE41, obtains extensive must the application.

In addition, because metallic substance is easy to reclaim, be easier to recycling than plastic prod, so help resources conservation and environment protection.

Description of drawings

With reference to the accompanying drawings, instance of the present invention is described.

Accompanying drawing 1. material hot treatment process schematic representations.

The age hardening behavior of accompanying drawing 2. alloys.

Accompanying drawing 3. is at the main strengthening phase of peak value timeliness stage alloy.

The mechanical property of alloy under accompanying drawing 4. room temperatures.

The creep property of accompanying drawing 5. alloys under 200 ℃.

Embodiment

Prepare burden according to alloying constituent provided by the invention, on the conventional, electric-resistance stove, carry out melting, in fusion process, burn, protect with flux in order to prevent and treat alloy with iron crucible.Adopt high-purity Mg and Zn ingot; Alloying element Gd; Nd and Zr are respectively with Mg-Gd, and the form of Mg-Y and Mg-Zr master alloy is added, and the melting of alloy and teeming temperature are respectively 750 ℃ and 730 ℃; Melt cast is become the slab ingot of 24 mm (thick) * 220 mm (length) * 90 mm (height), analyze the composition of alloy with inductively coupled plasma atomic emission spectrometer (ICP).According to the national standard requirement, the alloy of timeliness to peak value is cut into bar-shaped or tabular its mechanical property of evaluation.

Claims

1. heat resistance magnesium alloy that solidity to corrosion is good, its staple is: Gd:1 ~ 2%; Nd:2 ~ 3%; Zn:0.5 ~ 1.0%; Zr:0.5%; Other compositions are Mg and a spot of impurity element.

2. the content of impurity element must not be higher than: Si must not be higher than 0.01%, and Cu must not be higher than 0.008%, and Ni must not be higher than 0.001%, and Fe is not higher than 0.004%, and Al is not higher than 0.003%; Especially to control the content of Fe and Al in the alloy.