Method for preparing high strength and ductility magnesium-rare earth alloy through selective laser melting additive manufacturing technology

A technology of selective laser melting and magnesium-rare-earth alloys, which is applied in the direction of additive manufacturing, additive processing, and energy efficiency improvement. It can solve the problems of grain and eutectic phase coarseness, inclusion mechanical properties, composition segregation, etc. Low phase content, good product stability, and improved structure

Active Publication Date: 2020-01-14

SHANGHAI JIAO TONG UNIV

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Problems solved by technology

[0005] The purpose of the present invention is to fill the gap in the field of selective laser melting preparation of existing Mg-RE-(Zn)-Zr alloys, to provide a method for preparing high-strength and tough magnesium rare earth alloys by selective laser melting addit...

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Abstract

The invention provides a method for preparing high strength and ductility magnesium-rare earth alloy through a selective laser melting additive manufacturing technology. The method comprises the following steps that A, through a gas atomization method, Mg-RE-(Zn)-Zr alloy spherical powder is prepared; B, selective laser melting molding is carried out on the Mg-RE-(Zn)-Zr alloy spherical powder toobtain the high strength and ductility magnesium-rare earth alloy; and C, the magnesium-rare earth alloy made in the B is subjected to heat treatment: solid solution + aging treatment or aging treatment directly. Through regulating of selective laser melting process parameters (laser power, scanning speed, scanning interval, light spot diameter, layer thickness, interlayer corner, base plate preheating temperature, partition width and lap-joint area width and subsequent heat treatment process parameters (temperature and time), the microstructure and the mechanical property of the alloy are regulated. The selective laser melting technology is used firstly for preparing the high strength and ductility Mg-RE-(Zn)-Zr alloy.

Application Domain

Additive manufacturing apparatusTransportation and packaging +1

Technology Topic

Mechanical properties of carbon nanotubesHeat treated +6

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Examples

Experimental program(8)
Comparison scheme(5)

Example Embodiment

[0039] Example 1

[0040] This embodiment provides a method for preparing a high-strength and tough magnesium rare earth alloy by selective laser melting additive manufacturing technology, which specifically adopts the following steps:

[0041] 1) Prepare Mg-11.16Gd-1.72Zn-0.44Zr (wt.%) alloy powder by gas atomization, and sieve the alloy powder, select 300-500 mesh (average particle size is 42 μm) powder Perform selective laser melting molding.

[0042] 2) Put the powder into the powder bed of the selective laser melting equipment after drying at 200°C/5h in a vacuum drying box, preheat the substrate to 200°C, pass in the protective gas argon for gas circulation, and wait for the molding chamber When the oxygen and water vapor content in the room is lower than 100ppm, the selective laser melting molding starts.

[0043] 3) The laser power used in selective laser melting and molding is 80W, the scanning speed is 500mm/s, the scanning spacing is 100μm, the spot diameter is 100μm, the layer thickness is 30μm, the interlayer rotation angle is 73°, and the scanning strategy is a partitioned island scanning strategy , the width of the partition is 5mm, and the width of the overlapping area between different partitions is 0.2mm.

[0044] 4) The SLM state magnesium alloy prepared in the above 3) is subjected to T4 treatment: it is carried out in an air resistance furnace, and pyrite is put into the SO released by thermal decomposition. 2 The gas is used for flame retardant protection of the alloy, and a single-step solution treatment is adopted: solution at 480 °C for 1 hour, and then quenched in cold water at 20 °C.

[0045] 5) The T4 state magnesium alloy prepared in the above 4) is artificially aged T6 in a constant temperature oil bath furnace, and a single-step aging treatment is adopted: the aging temperature is 200 ° C, the time is 64 h, and then quenched in 20 ° C cold water.

[0046] 6) The SLM state magnesium alloy prepared in the above 3) is subjected to T5 treatment: in a constant temperature oil bath furnace, a single-step aging treatment is adopted: the aging temperature is 200 ° C, the time is 64 h, and then quenched in 20 ° C cold water.

[0047] 7) The SLM state, T4 state, T6 state and T5 state magnesium alloy prepared in the above 3), 4), 5) and 6) are subjected to room temperature tensile experiments, and the tensile machine is Zwick BTC-Z100 electronic universal material testing machine , the tensile test rate is 0.5mm/min.

[0048] The structure of the obtained alloy in SLM state is as follows: figure 1 Shown: showing typical characteristics of rapid solidification, the ɑ-Mg matrix has fine and uniform grains (1-3 μm), and the content of β-phase at the grain boundary is small and finely dispersed. The room temperature tensile properties of Mg-11.16Gd-1.72Zn-0.44Zr (wt.%) alloys (SLM, SLM-T4, SLM-T6, SLM-T5) in different states are as follows figure 2 As shown, the room temperature tensile yield strength of the SLM state is 252 MPa, the tensile strength is 275 MPa, and the elongation is 4.3%; the strength and plasticity are improved after the solution + aging heat treatment, and the room temperature tensile yield strength of the T6 state is as high as 260 MPa, The tensile strength is 346MPa, and the elongation is 4.8%; the strength of the alloy is greatly improved after direct aging treatment, but the plasticity is poor. The room temperature tensile yield strength of the T5 state is as high as 365MPa, the tensile strength is 385MPa, and the elongation is 2.3%. .

Example Embodiment

[0049] Example 2

[0050] This embodiment provides a method for preparing a high-strength and tough magnesium rare earth alloy by selective laser melting additive manufacturing technology, which specifically adopts the following steps:

[0051] 1) Mg-14.92Gd-0.30Zr (wt.%) alloy powder was prepared by gas atomization, and the alloy powder was sieved, and the powder of 300-500 mesh (average particle size was 42 μm) was selected for laser selection. Melt molding.

[0052] 2) Put the powder into the powder bed of the selective laser melting equipment after drying at 200°C/5h in a vacuum drying box, preheat the substrate to 150°C, pass in the protective gas argon for gas circulation, and wait for the molding chamber When the oxygen and water vapor content in the room is lower than 100ppm, the selective laser melting molding starts.

[0053] 3) The laser power used in selective laser melting molding is 80W, the scanning speed is 100mm/s, the scanning spacing is 100μm, the spot diameter is 100μm, the layer thickness is 2μm, the interlayer rotation angle is 70°, and the scanning strategy is a partitioned island scanning strategy , the width of the partition is 4mm, and the width of the overlapping area between different partitions is 0.3mm.

[0054] 4) The SLM state magnesium alloy prepared in the above 3) is subjected to T4 treatment: it is carried out in an air resistance furnace, and pyrite is put into the SO released by thermal decomposition. 2 The gas is used for flame retardant protection of the alloy, and a single-step solution treatment is adopted: solution treatment at 520 °C for 15 minutes, followed by quenching in cold water at 20 °C.

[0055] 5) The T4 state magnesium alloy prepared in the above 4) is artificially aged T6 in a constant temperature oil bath furnace, and a single-step aging treatment is adopted: the aging temperature is 200 ° C, the time is 64 h, and then quenched in 20 ° C cold water.

[0056] 6) The SLM state magnesium alloy prepared in the above 3) is subjected to T5 treatment: in a constant temperature oil bath furnace, a single-step aging treatment is adopted: the aging temperature is 200 ° C, the time is 64 h, and then quenched in 20 ° C cold water.

[0057] 7) The SLM state, T4 state, T6 state and T5 state magnesium alloy prepared in the above 3), 4), 5) and 6) are subjected to room temperature tensile experiments, and the tensile machine is Zwick BTC-Z100 electronic universal material testing machine , the tensile test rate is 0.5mm/min.

[0058] The obtained SLM alloy exhibits typical characteristics of rapid solidification and fine grains. The α-Mg matrix has fine and uniform grains (1-3 μm), and the content of β phase in the grain boundary is small and finely dispersed. The room temperature tensile yield strength of the SLM state is 306MPa, the tensile strength is 310MPa, and the elongation is 0.7%; the room temperature tensile yield strength of the T6 state is as high as 308MPa, the tensile strength is 337MPa, and the elongation is 0.3%; the room temperature of the T5 state The tensile yield strength is as high as 340MPa, the tensile strength is 343MPa, and the elongation is 0.4%.

Example Embodiment

[0059] Example 3

[0060] This embodiment provides a method for preparing a high-strength and tough magnesium rare earth alloy by selective laser melting additive manufacturing technology, which specifically adopts the following steps:

[0061] 1) Prepare Mg-19.89Gd (wt. %) alloy powder by gas atomization, sieve the alloy powder, and select powder of 500 mesh or more (average particle size is 34 μm) for selective laser melting molding.

[0062] 2) Put the powder into the powder bed of the selective laser melting equipment after drying at 150°C/4h in a vacuum drying box, preheat the substrate to 100°C, pass in the protective gas argon for gas circulation, and wait for the molding chamber When the oxygen and water vapor content in the room is lower than 100ppm, the selective laser melting molding starts.

[0063] 3) The laser power used in selective laser melting molding is 160W, the scanning speed is 1000mm/s, the scanning spacing is 50μm, the spot diameter is 65μm, the layer thickness is 40μm, the interlayer rotation angle is 75°, and the scanning strategy is a partitioned island scanning strategy , the width of the partition is 3mm, and the width of the overlapping area between different partitions is 0.1mm.

[0064] 4) The SLM state magnesium alloy prepared in the above 3) is subjected to T4 treatment: it is carried out in an air resistance furnace, and pyrite is put into the SO released by thermal decomposition. 2 The gas is used to protect the alloy from flame retardancy, and a single-step solution treatment is adopted: solid solution at 520 °C for 2 hours, and then quenched in cold water at 20 °C.

[0065] 5) The T4 state magnesium alloy prepared in the above 4) was artificially aged T6 in a constant temperature oil bath furnace, and a single-step aging treatment was adopted: the aging temperature was 175 ° C, the time was 512 h, and then quenched in 20 ° C cold water.

[0066] 6) The SLM state magnesium alloy prepared in the above 3) is subjected to T5 treatment: in a constant temperature oil bath furnace, a single-step aging treatment is adopted: the aging temperature is 175 ° C, the time is 512 h, and then quenched in 20 ° C cold water.

[0067] 7) The SLM state, T4 state, T6 state and T5 state magnesium alloy prepared in the above 3), 4), 5) and 6) are subjected to room temperature tensile experiments, and the tensile machine is Zwick BTC-Z100 electronic universal material testing machine , the tensile test rate is 0.5mm/min.

[0068] The obtained SLM alloy exhibits typical characteristics of rapid solidification and fine grains. The α-Mg matrix has fine and uniform grains (1-3 μm), and the content of β phase in the grain boundary is small and finely dispersed. The room temperature tensile yield strength of the SLM state is 358MPa, the tensile strength is 362MPa, and the elongation is 0.7%; the room temperature tensile yield strength of the T6 state is as high as 365MPa, the tensile strength is 374MPa, and the elongation is 0.5%; The room temperature of the T5 state The tensile yield strength is as high as 410MPa, the tensile strength is 418MPa, and the elongation is 0.3%.

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PUM

Property	Measurement	Unit
Tensile yield strength	252.0	mPa
Tensile strength	275.0	mPa
Tensile yield strength	260.0	mPa
tensile		MPa
Particle size		Pa
strength	10

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Method for preparing high strength and ductility magnesium-rare earth alloy through selective laser melting additive manufacturing technology

AI-Extracted Technical Summary

Problems solved by technology

Abstract

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Example Embodiment

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Description & Claims & Application Information

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