CN1265007C - Mg-Zn-Al based magnesium alloy and its smelting method - Google Patents

Abstract

The present invention discloses a Mg-Zn-Al group magnesium alloy and a melting method thereof. The alloy comprises the chemical components of the percentage: 6% to 15% of Zn, 1% to 9% of Al, 0.1% to 0.5% of Mn, 0.1% to 0.5% of Ca, 0.03% to 0.5% of Sr, 0.05% to 1% of rare-earth elements Mg as the rest, and unavoidable impurity elements, wherein one or several kinds of the Ca, the Sr and the rare-earth elements are freely selected. The Mg-Zn-Al group magnesium alloy of the present invention has high room-temperature and high-temperature mechanical property. At a room temperature, tensile strength sigma b is from 168 to 262MPa, yield strength sigma s is from 77 to 162MPa, and elongation rate delta is from 3% to 8%. The present invention has the advantages of good casting property and low cost.

Description

Mg-Zn-Al base magnesium alloy and melting method thereof

Technical field

Originally relate to invention and relate to a kind of Mg-Zn-Al base magnesium alloy and melting method thereof.The category that belongs to industrial magnesium alloy.

Background technology

At present, along with energy-conserving and environment-protective and automotive performance promote improving constantly of requiring, magnesium alloy is because little, the specific tenacity specific rigidity height of density, good casting property, especially be easy to die cast, remove this and also have good damping property and be easy to advantage such as recovery, present flourish gesture in the application of automotive industry.The continuous expansion of on automobile, using along with magnesium alloy, component are to the structural part and the functional part development of critical positions such as gear box casing, engine support, piston, wheel hub as from original panel board, car door etc., people also satisfy the various different magnesium alloy that require in exploitation, as economical magnesium alloy, high-strength-toughness magnesium alloy, high temperature and creep resistance magnesium alloy etc.

Traditional magnesium alloy such as AZ91D, AM60B, AS41, AE42 etc. have obtained to use widely, still are several magnesium alloy of present application quantity maximum.But these alloys often all have certain shortcoming, as creep-resistant property lower (AZ91D), castability relatively poor (AS41) or cost higher (WE43) etc.

Summary of the invention

The purpose of this invention is to provide a kind of Mg-Zn-Al base magnesium alloy.It can satisfy the mechanical property requirements of general component, also can be used for the high requirement occasion, satisfies the requirement of higher mechanical property or higher temperatures creep-resistant property, and cost is relatively low simultaneously.

Another object of the present invention provides a kind of melting method of Mg-Zn-Al base magnesium alloy.

For achieving the above object, the present invention takes following technical scheme:

A kind of magnesium alloy of Mg-Zn-Al base, in this alloy the mass percent of chemical ingredients be:

Zn 11％～15％；

Al 1％～9％；

Mn 0.1％～0.5％；

In Ca, Sr and the RE elements such as (rare earth elements) one or more, wherein, their mass percent is:

Ca 0.1％～0.5％、

Sr 0.03％～0.5％、

Rare earth element 0.05%～1%;

Surplus is Mg and the impurity element that is difficult to avoid.

Alloy series of the present invention is to be matrix with Mg-Zn-Al, suitably adds alloying elements such as Mn, Ca, Sr, RE, thereby improves its over-all properties.

In the magnesium alloy of above-mentioned Mg-Zn-Al base, the mass percent of Al is preferably 1%～5% in the described alloy.

In the magnesium alloy of above-mentioned Mg-Zn-Al base, described rare earth element is one or more among mishmetal, Nd, Dy, Y and the Gd.

In the magnesium alloy of above-mentioned Mg-Zn-Al base, described impurity element is impurity elements such as Fe, Ni, Cu, and their mass percents in alloy are controlled in 0.03% mass percent.

The magnesium alloy of Mg-Zn-Al base of the present invention at room temperature, its tensile strength sigma _bBe 168～262MPa, yield strength σ _sBe 77～162MPa, unit elongation δ is 3%～8%.

A kind of method of magnesium alloy of melting Mg-Zn-Al base, this method comprises the steps:

(1) prepare burden by following mass percent:

Zn 11％～15％；

Al 1％～9％；

Mn 0.1％～0.5％；

In Ca, Sr and the rare earth element one or more, wherein, their mass percent is:

Ca 0.1％～0.5％、

Sr 0.03％～0.5％、

Rare earth element 0.05%～1%;

Surplus is Mg;

(2) adopt flux covering protection or gas shield melting, protection gas is 0.6%～5%SO ₂+ dry air places the crucible heat fused to become liquation with alloy element Zn with Al the matrix metal Mg of proportional quantity; Perhaps earlier Mg is melted, add Zn and Al fusing then;

(3) in liquation, add the Mn of proportional quantity with the form of Mg-Mn master alloy;

(4) in Ca, Sr and the rare earth element one or more are added in the liquation of step (3) according to said sequence, and liquation is fully stirred, promptly make alloy after the casting.

Advantage of the present invention is:

(1) magnesium alloy of Mg-Zn-Al base of the present invention has higher room-temperature mechanical property.At room temperature, its tensile strength sigma _bBe 168～262MPa, yield strength σ _sBe 77～162MPa, unit elongation δ is 3%～8%.

(2) this alloy has castability preferably.

(3) this alloy has lower cost.

Embodiment

Embodiment 1

Prepare burden by following mass percent:

Zn 9.1％

Al 3.9％

Mn 0.2％

Nd 0.18％

Surplus is a magnesium

Get MAGNESIUM METAL, zinc and the aluminium of said ratio amount, together put into the cast steel with high chromium crucible, heat fused becomes liquation.Melting process sprinkles the MAGNESIUM METAL covering flux in the metallic surface.When melt temperature reaches 730 ℃, in liquation, add and contain the Mg-Mn master alloy of proportional quantity manganese, the rare earth metal Nd of said ratio amount, and the agitation as appropriate liquation, promptly make alloy after the casting.When stirring, in the Metal Melting furnace, feed 0.6%～5%SO ₂+ dry air is protected.

The mechanical property of this alloy is: σ _b: 202MPa, σ _s: 124MPa, δ: 4%.

Embodiment 2

Prepare burden by following mass percent:

Zn 12.7％

Al 3.7％

Mn 0.2％

Sr 0.15％

Dy 0.1％

Surplus is a magnesium

Get the MAGNESIUM METAL of said ratio amount and put into the cast steel with high chromium crucible, heat fused becomes liquation, puts into the Zn and the Al fusing of said ratio amount then.Melting process sprinkles the MAGNESIUM METAL covering flux in the metallic surface.When melt temperature reaches 740 ℃, in liquation, add Mg-Mn master alloy and the proportional quantity Sr that contains proportional quantity manganese, and stir short its fusing of liquation.In liquation, add the rare earth element Dy of said ratio amount then, and stir short its fusing of liquation.In alloying process, feed 0.6%～5%SO in the Metal Melting furnace ₂+ dry air is protected.

The mechanical property of this alloy is: σ _b: 193MPa, σ _s: 109MPa, δ: 3%.

Embodiment 3-10

The one-tenth of embodiment 3-10 is grouped into and proportional quantity sees the following form.Rare earth element wherein can be mishmetal, Nd, Dy, Y or Gd, or its combination.The melting method of these embodiment and embodiment 1 and embodiment 2 are similar.

Embodiment	Zn (quality %)	Al (quality %)	Mn (quality %)	Ca (quality %)	Sr (quality %)	RE (quality %)	Mg (quality %)
								3	7.1	3.3	0.2	0.3	/	/	Surplus
4	8.2	4.1	0.3	0.2	0.1	/	Surplus
								5	9.6	3.8	0.2	/	/	0.1	Surplus
6	11.0	4.4	0.2	/	0.3	0.1	Surplus
								7	12.1	6.0	0.2	0.1	/	0.3	Surplus
8	13.0	5.5	0.3	/	0.3	/	Surplus
								9	13.5	4.8	0.3	/	/	0.3	Surplus
10	14.2	4.8	0.2	/	0.2	0.2	Surplus

The magnesium alloy alloy at room temperature mechanical property of resulting Mg-Zn-Al base is all in following ranges in embodiment 3-10: its tensile strength sigma _bBe 168～262MPa, yield strength σ _sBe 77～162MPa, unit elongation δ is 3%～8%.

The invention is not restricted to these concrete combinations of the foregoing description.

Claims (5)

1, a kind of magnesium alloy of Mg-Zn-Al base is characterized in that: the mass percent of the chemical ingredients in this alloy is:

Zn 11％～15％；

Al 1％～9％；

Mn 0.1％～0.5％；

In Ca, Sr and the rare earth element one or more, wherein, their mass percent is:

Ca 0.1％～0.5％、

Sr 0.03％～0.5％、

Rare earth element 0.05%～1%;

Surplus is Mg and the impurity element that is difficult to avoid.

2, the magnesium alloy of Mg-Zn-Al base according to claim 1 is characterized in that: the mass percent of Al is 1%～5% in the described alloy.

3, the magnesium alloy of Mg-Zn-Al base according to claim 1 is characterized in that: described rare earth element is one or more among mishmetal, Nd, Dy, Y and the Gd.

4, the magnesium alloy of Mg-Zn-Al base according to claim 1 is characterized in that: described impurity element is impurity elements such as Fe, Ni, Cu, and their mass percents in alloy are controlled in 0.03% mass percent.

5, a kind of method of magnesium alloy of melting Mg-Zn-Al base, it is characterized in that: this method comprises the steps:

(1) prepare burden by following mass percent:

Zn 11％～15％；

Al 1％～9％；

Mn 0.1％～0.5％；

In Ca, Sr and the rare earth element one or more, wherein, their mass percent is:

Ca 0.1％～0.5％、

Sr 0.03％～0.5％、

Rare earth element 0.05%～1%;

Surplus is Mg;

(2) adopt flux covering protection or gas shield melting, protection gas is 0.6%～5%SO ₂+ dry air places the crucible heat fused to become liquation with alloy element Zn with Al the matrix metal Mg of proportional quantity; Perhaps earlier Mg is melted, add Zn and Al fusing then;

(3) in liquation, add the Mn of proportional quantity with the form of Mg-Mn master alloy;

(4) in Ca, Sr and the rare earth element one or more are added in the liquation of step (3) according to said sequence, and liquation is fully stirred, promptly make alloy after the casting.