CN102061415A

CN102061415A - Die cast magnesium alloy with heat cracking resistance and high fluidity

Info

Publication number: CN102061415A
Application number: CN 201110021888
Authority: CN
Inventors: 单巍巍; 李远发; 唐定骧
Original assignee: Chong Jin Technology (shenzhen) Co Ltd
Current assignee: KA SHUI TECHNOLOGY (HUIZHOU) CO., LTD.
Priority date: 2011-01-19
Filing date: 2011-01-19
Publication date: 2011-05-18
Anticipated expiration: 2031-01-19
Also published as: CN102061415B

Abstract

The invention provides a die cast magnesium alloy with heat cracking resistance and high fluidity, which comprises magnesium, aluminum and zinc and further comprise the following components in percentage by weight: 0.1-0.5% of cerium, 0.1-0.5% of lanthanum, 0.1-0.5% of yttrium, 0.01-0.2% of gadolinium, 0.01-0.3% of holmium, 0.01-0.5% of strontium, or/and 0.1-0.8% of calcium. The die cast magnesium alloy with heat cracking resistance and high fluidity has higher casting property.

Description

The high workability diecast magnesium alloy is split in a kind of heat resistanceheat resistant

Technical field

The present invention relates to the metallic substance technical field, the high workability diecast magnesium alloy is split in particularly a kind of heat resistanceheat resistant.

Background technology

Magnesium alloy (claiming that Mg-Al-Zn is alloy for die casting) is the maximum important alloy of consumption in the commercial magnesium alloy.Magnesium alloy has in light weight, damping noise reduction, and anti-electromagnetic-radiation, thermal conductivity is good, reclaims advantage, especially magnesium resources such as not producing environmental pollution abundant especially (and iron and steel, aluminium, copper resource are exhausted day by day), is described as the green structured material of 21 century lightweight.Magnesium is the principal element (accounting for 90% quality usually) in the magnesium alloy, because the chemical property of magnesium is active, generates magnesium oxide easily, magnesium oxide is mingled with; The solubleness of hydrogen in magnesium alloy is than big two orders of magnitude of aluminium; Other alloying element in the magnesium alloy such as rare earth and zirconium and hydrogen effect generate hydride; Magnesium and water effect produce Mg (OH) ₂And H2, also often there are solvent impurity and metal inclusion to occur in the magnesium alloy.The existence of these impurity, becoming Mg-Al is the source of alloy major defect-shrinkage porosite pore and hot tearing, and alloy viscosity is increased, and mobile reduction, cavity filling, feeding are bad, and foundry goods release property, resistance to air loss, good article rate reduce.

Summary of the invention

The invention provides and a kind ofly have the more heat resistanceheat resistant of high casting property and split the high workability diecast magnesium alloy.

To achieve these goals, the invention provides following technical scheme:

The high workability diecast magnesium alloy is split in a kind of heat resistanceheat resistant, comprises magnesium, aluminium, and zinc, it also comprises according to weight percent: cerium 0.1-0.5%; Lanthanum 0.1-0.5%; Yttrium 0.1-0.5%; Gadolinium 0.01-0.2%; Holmium 0.01-0.3%; Strontium 0.01-0.5%; Or/and calcium 0.1-0.8%.

Preferably, described heat resistanceheat resistant is split the high workability diecast magnesium alloy and is also comprised: cerium 0.2%, lanthanum 0.3%; Yttrium 0.3%; Gadolinium 0.05%; Holmium 0.05%; Strontium 0.3%; Or/and calcium 0.3%.

By implementing above technical scheme, has following technique effect: the invention provides a kind of heat resistanceheat resistant and split the high workability diecast magnesium alloy, light rare earths and heavy rare earth element combination, it is bigger to bring into play light rare earths proportion rare earth chemistry activity, gives full play to effect of light rare earths purification and impurity removal and refined crystalline strengthening effect; And the solid solubility that heavy rare earths splits in the high workability diecast magnesium alloy in heat resistanceheat resistant is bigger, can give full play to its solution strengthening effect.

Rare earth and the combination of each alkaline earth element are given full play to rare earth and alkaline earth element and are all resisted hot tearing high workability diecast magnesium alloy generation inhibited oxidation, stop each reinforced alloys usefulness of burning, as: the adding of strontium can promote the hot-cracking resistance of alloy.

Various elements all add with trace ingredients, and add-on is no more than each element and splits solid solubility in the high workability diecast magnesium alloy in heat resistanceheat resistant, avoids forming compound between refractory metal pockety, reduces the alloy casting performance; Reduce cost of alloy.

Embodiment

Technical scheme is for a better understanding of the present invention described embodiment provided by the invention below in detail.

The embodiment of the invention provides a kind of heat resistanceheat resistant to split the high workability diecast magnesium alloy, comprise magnesium, also can be magnalium, also can be magnesium, aluminum and zinc alloy, the ratio of this magnesium and aluminium can make up as required, split the weight percent of the gross weight of high workability diecast magnesium alloy according to this heat resistanceheat resistant, also comprise: cerium 0.1-0.5%; Lanthanum 0.1-0.5%; Yttrium 0.1-0.5%; Gadolinium 0.01-0.2%; Holmium 0.01-0.3%; Strontium 0.01-0.5%; Among the calcium 0.1-0.8% any one or several combination arbitrarily.

Preferably, this heat resistanceheat resistant is split the high workability diecast magnesium alloy and is also comprised according to weight percent: cerium 0.2%, lanthanum 0.3%; Yttrium 0.3%; Gadolinium 0.05%; Holmium 0.05%; Strontium 0.3%; In the calcium 0.3% any one or several combination arbitrarily.

In the foregoing description, utilize stronger rare earth of chemically reactive surface specific activity magnesium and strontium, calcium to make to add the cleaning action of element, prevent that heat resistanceheat resistant from splitting high workability diecast magnesium alloy oxygenatingization, nitrogenize and removing impurity.

The calcium metal of the strontium in the rare earth, metal alkaline earth is the stronger element of chemically reactive, surfactivity than magnesium, allow strontium, calcium at first with impurity effects such as O2, H2, N2, H2O, Cl2, Fe, and be removed/reduce its harm.Allow the oxide compound of these interpolation elements and the complex oxide film that the magnesium in the alloy, aluminum oxide form densification stop alloy to be diffused into alloy inside by airborne oxygen, hydrogen, nitrogen.

Utilizing multi-element additives to promote Mg-Al is the flowability of alloy:

Most magnesium-rare earth, magnesium-alkaline earth binary alloy all have simple eutectic reaction, and they join has increased the eutectic deal among the Mg-Al, improved its flowability; Moreover rare earth metal is can reduce its surface tension in the adding Mg-Al alloy of surface active element and improve flowability.

The adding of trace rare-earth metal can refining Mg-Al be an alloy organizing, and the alkaline-earth metal strontium can promote hot-cracking resistance.

Most rare earth metals are the same with magnesium, belong to intensive hexagonal together, and heavy rare earth metal fusing point height can play the forming core central role, and light rare earth metal is enriched in the alloy solid-liquid forward position, causes constitutional supercooling, promote nucleation, stop grain growth; Thin crystalline substance is many more, and the more little then shrinkability of dendrite interval is more little, and the trend that produces thermal crack is low more, and body of casting yield rate is high more.

The present invention is provided more specifically embodiment below:

Embodiment 1 (test number 1):

With commercially available AZ91D alloy [the most general a kind of of present commercial magnesium alloy, it is the trade mark call among the U.S. ASTM, wherein A represents metallic aluminium Al, Z represents metallic zinc Zn, 9 content of representing aluminium are for being similar to 9%, 1 content of representing zinc for being similar to 1%, and D is meant die casting (diecasting) alloy, wherein the trade mark of the corresponding GB the inside of China is YZMgAl9Zn1 (D)] 800 kilograms put into the smelting iron crucible of combustion gas heating, fusing heats up under argon shield; Stirred 15 minutes in the time of 700 ℃, drag for slag, leave standstill on 30 minutes.Adopt mould (this mould can obtain the standard coupon simultaneously and measure alloy mobile length in spiral tube), under 640 ℃, in hot chamber machine, carry out die casting, get 10 die casting samples alloy die casting performance, outward appearance, form, micro-, tissue are observed test.Present embodiment is as the reference contrast, and it mainly the results are shown in table 1.

Embodiment 2 (test number 2):

On the basis of embodiment 1, make alloy be warmed up to 750 ℃ AZ91D and add Mg-Cet and Mg-La master alloy, the Ce amount that adds accounts for 0.2% (mass percent) its castability that 0.3% (mass percent) of alloy total amount, the La amount that adds account for the alloy total amount and obviously promotes (seeing Table 1), and helicoidal flow length increases about 30%. than AZ91D

Embodiment 3 (test number 3):

Experiment condition and process are substantially the same manner as Example 2, just except adding Ce0.3%, outside the La0.2%, add Y0.08% again again, and (Gd+Ho) 0.02%, its castability has a distinct increment again.

Embodiment 4 (test number 4):

Experiment condition and process and embodiment roughly the same, different persons increase to 0.2% with the Y add-on, (Gd+Ho) add-on increases to 0.1%, the total add-on that is heavy rare earths is 0.3% (mass percent), having added Sr0.1%. result and list table 1. in it is mobile and cracking resistance line performance is all fine in order to prevent that alloy from cracking, is that demolding performace decreases; Its reason may be that the heavy rare earth element add-on is higher, has generated high melting compound, alloy viscosity increased, demoulding difficulty; Alloy temperature is brought up to 680 ℃ carry out die casting.Help to solve the problem of demoulding difficulty.

Table 1: more trace elements is to AZ91D magnesium alloy cast Effect on Performance

Annotate: " * " is many more, and performance is good more.

Alloy (AZ91D+Ce0.3%+La0.2%+Y0.08%+Gd0.01%+Ho0.01%) foundry goods in alloy A Z91D in the test number 1 and the test number 3 is carried out solidity to corrosion and mechanical property compares test, the results are shown in Table 2.As seen from Table 2, add more trace elements and really promote the performance that high workability diecast magnesium alloy foundry goods is split in heat resistanceheat resistant.This matches with the result who promotes the alloy casting performance.

Table 2: more trace elements is to the influence of AZ91D magnesium alloy over-all properties

As can be seen from Table 2, (the corrosion resisting property rank that adds Ce, La and micro-Y and (Gd, Ho) is the highest, and its tensile strength and unit elongation also promote to some extent for test number 3.

More than the high workability diecast magnesium alloy split in a kind of heat resistanceheat resistant that the embodiment of the invention provided be described in detail, for one of ordinary skill in the art, thought according to the embodiment of the invention, part in specific embodiments and applications all can change, in sum, this description should not be construed as limitation of the present invention.

Claims

1. the high workability diecast magnesium alloy is split in a heat resistanceheat resistant, comprises magnesium, and aluminum and zinc is characterized in that, according to weight percent, also comprises: cerium 0.1-0.5%; Lanthanum 0.1-0.5%; Yttrium 0.1-0.5%; Gadolinium 0.01-0.2%; Holmium 0.01-0.3%; Strontium 0.01-0.5%; Or/and calcium 0.1-0.8%.

2. the high workability diecast magnesium alloy is split in a kind of according to claim 1 heat resistanceheat resistant, it is characterized in that, also comprises: cerium 0.2%, lanthanum 0.3%; Yttrium 0.3%; Gadolinium 0.05%; Holmium 0.05%; Strontium 0.3%; Or/and calcium 0.3%.