CN108103370A

CN108103370A - A kind of fabricated in situ Mg2Si/Al composite materials

Info

Publication number: CN108103370A
Application number: CN201611045073.8A
Authority: CN
Inventors: 刘芳
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-11-24
Filing date: 2016-11-24
Publication date: 2018-06-01

Abstract

A kind of fabricated in situ Mg₂Si/Al composite materials are prepared for Mg by stirring casting method₂Si/Al in-situ composites, Mg₂White dendroid, the enhancing tiny of particle are uniformly distributed in the base Si in the composite, and enhancing phase and the interface cleanness of matrix are pollution-free；Si and Mg reactions completely generate Mg₂Si, a small amount of Mg also generate Mg with Al reactions_l7Al_l2, micro Mg is present in solid solution thereof in composite material.Mg₂Microhardness, wearability and the damping and amortization of Si/Al composite materials are significantly improved, wherein Mg₂When Si contents are 10%, which improves 1.71 times with respect to the microhardness of fine aluminium, and wearability improves 2.42 times, and damping and amortization improves 9.85 times.

Description

A kind of fabricated in situ Mg2Si/Al composite materials

Technical field

The present invention relates to a kind of powdered metallurgical material more particularly to a kind of fabricated in situ Mg₂Si/Al composite materials.

Background technology

Particle enhanced aluminum-based composite material has high specific strength, specific stiffness height, high-temperature behavior is good, damping capacity is good, heat is swollen The superior functions such as swollen coefficient is low, therefore be concerned.The preparation method of aluminum matrix composite is divided into two classes:Outer addition and original position are certainly It thinks of a way.The aluminum matrix composite of in-situ authigenic, enhancing is mutually preferable with the compatibility of matrix, and clean interfaces, pollution-free, particle is opposite It is tiny, and solve the insoluble field trash of outer addition, between interfacial reaction and particle and matrix the problems such as wetability.Thus More favored.

Mg₂Si has high-melting-point, high rigidity, low-density, low thermal coefficient of expansion and high elasticity modulus etc., is well suited as The reinforcement of aluminum matrix composite.Mg can be prepared using liquid molten method₂Si/Al enhances the spontaneous composite wood of eutectic Al-Si alloy Material.Show near liquidus curve, when pouring temperature is 720 DEG C, crystal grain is uniformly tiny；Pr alterants are to primary silicon and eutectic structure There is apparent thinning effect, and refine Mg₂Si, change its pattern and size, the mechanical property of alloy can be improved.

The content of the invention

The purpose of the invention is to improve the wearability of aluminum matrix composite, a kind of fabricated in situ Mg is devised₂Si/Al Composite material.

The technical solution adopted by the present invention to solve the technical problems is：

Fabricated in situ Mg₂The raw material for preparing of Si/Al composite materials includes：Matrix is commercial-purity aluminium, and reinforcement is silica flour (75 μm) React generation Mg at high temperature with AZ31D magnesium alloys₂Si。

Fabricated in situ Mg₂The preparation process of Si/Al composite materials is：Resistance furnace is first warming up to 720 DEG C, aluminium ingot is put into In crucible；Molten aluminum is superheated to 870 DEG C, adds in the silica flour through 200 DEG C of pretreatment 2h：Adds in AZ31D magnesium alloys and adopts after 5min It is stirred with homemade three leaves blender, Si and Mg is allowed fully to react；After stirring 10min, cast molding.

Fabricated in situ Mg₂The detecting step of Si/Al composite materials is：It is carried out using D8-ADVANCE types X-ray diffractometer The material phase analysis of composite material；With in JSM-6360LA type scanning electron microscopic observation composite material microscopic structures enhance particle it is big Small, pattern and distribution.The Mg that will be prepared by stirring casting₂It is processed into respectively on Si/Al in-situ composite cutting on line machines The sample of 10mmX10mmX15mm, 7mmX7mmX30mm, 40mmX5mmX1mm are polished smooth surface with sand paper.It is respectively adopted XHV-1000 type automatic turret digital displays microhardness testers, M-2000 types friction and wear tester, TPA-8 type precisions rock mechanoscopy The microhardness of instrument test compound material.To ensure the accuracy of data, four different points are chosen on each sample and are carried out Hardness test is averaged.Wearability experiment power is 400N, rotating speed 180r/min.After before experiment sample is cleaned, dry, Using SHIMA-DZUAUY220 type electronic balance weighings, cleaning, dry weighing after abrasion 5min in experimental machine are placed into.Repeatedly 4 It is secondary.Damping and amortization experimental temperature is 30.8 DEG C, setpoint frequency 1.000Hz.

The beneficial effects of the invention are as follows：

Mg is prepared for by mechanical agitation casting₂Si/Al in-situ composites, Mg₂Si white branches in the composite Shape, the enhancing tiny of particle are uniformly distributed in the base, enhancing phase and the interface cleanness of matrix, pollution-free；Si and Mg react completely Generate Mg₂Si, a small amount of Mg also generate Mg with Al reactions_l7Al_l2, micro Mg is present in solid solution thereof in composite material. Mg₂Microhardness, wearability and the damping and amortization of Si/Al composite materials are improved, wherein Mg₂When Si contents are lO%, this is multiple Condensation material improves 1.71 times with respect to the microhardness of fine aluminium, and wearability improves 2.42 times, and Internal friction improves 9.85 times.

Specific embodiment

Case study on implementation 1：

Fabricated in situ Mg₂The raw material for preparing of Si/Al composite materials includes：Matrix is commercial-purity aluminium, and reinforcement is silica flour (75 μm) React generation Mg at high temperature with AZ31D magnesium alloys₂Si.Fabricated in situ Mg₂The preparation process of Si/Al composite materials is：First by electricity Resistance stove is warming up to 720 DEG C, and aluminium ingot is put into crucible；Molten aluminum is superheated to 870 DEG C, adds in the silica flour through 200 DEG C of pretreatment 2h： Is added in AZ31D magnesium alloys and is stirred using homemade three leaves blender after 5min, and Si and Mg is allowed fully to react；After stirring 10min, Cast molding.Fabricated in situ Mg₂The detecting step of Si/Al composite materials is：It is carried out using D8-ADVANCE types X-ray diffractometer The material phase analysis of composite material；With in JSM-6360LA type scanning electron microscopic observation composite material microscopic structures enhance particle it is big Small, pattern and distribution.The Mg that will be prepared by stirring casting₂It is processed into respectively on Si/Al in-situ composite cutting on line machines The sample of 10mmX10mmX15mm, 7mmX7mmX30mm, 40mmX5mmX1mm are polished smooth surface with sand paper.It is respectively adopted XHV-1000 type automatic turret digital displays microhardness testers, M-2000 types friction and wear tester, TPA-8 type precisions rock mechanoscopy The microhardness of instrument test compound material.To ensure the accuracy of data, four different points are chosen on each sample and are carried out Hardness test is averaged.Wearability experiment power is 400N, rotating speed 180r/min.After before experiment sample is cleaned, dry, Using SHIMA-DZUAUY220 type electronic balance weighings, cleaning, dry weighing after abrasion 5min in experimental machine are placed into.Repeatedly 4 It is secondary.Damping and amortization experimental temperature is 30.8 DEG C, setpoint frequency 1.000Hz.

Case study on implementation 2：

The Mg prepared by stirring casting method₂Si/Al in-situ composite hardness is significantly improved, wherein, Mg₂Si contents 1.71 times are enhanced for 10% highest.With Mg₂Si contents increase, and the microhardness of the composite material is also increasing.This is because Intermetallic compound Mg₂Si has high hardness, is evenly distributed in aluminum substrate, and the reinforcement of high rigidity plays matrix bright Aobvious humidification.In addition, enhancing particle serves as nucleating agent crystal grain in the solidification of composite material and refined, effectively enhance The hardness of the composite material.Second in the composite material meets generates interface with matrix.It generates, can carry with a large amount of dislocations The microhardness of the high composite material.

Case study on implementation 3：

Mg₂The wearability of Si/Al in-situ composites is significantly improved.Wherein Mg₂When Si contents are 10%, this is compound Material improves 2.42 times with respect to the wearability of fine aluminium.This is because it is generated by reaction in-situ with high intensity and wear-resisting The Mg of property₂Si is evenly distributed in composite material, on the one hand forms dislocation pinning effect, makes composite material in shearing force Under the action of deformation suffer restraints, prevent the progress of sliding；On the other hand, Mg₂The generation of Si is in the solidification of composite material Nucleating agent is acted as in the process.Can effective crystal grain thinning, improve material property.As time increases, Mg₂Si/Al is multiple in situ Weight loss of the condensation material in process of friction and wear also increases, but is not linear in the weight loss of each stage composite material Relation.It can be seen that by the slope of weight loss, in the 5-10min of abrasion, the rate of wear of material is relatively small.10min The speed worn afterwards gradually increases.This is because before in 10min, Mg₂The friction mill of the experimental sample of Si/Al composite materials Damage is in running in stage, and experimental sample and the smaller of contact area of abrasion machine at this time is under the action of shearing force, composite material Surface moulding flowing occurs, high salient point is ground off, the surface mill of sample it is smooth.Since specimen surface has firm oxidation Film hinders the progress of abrasion to a certain extent：And Mg at this time₂Si intermetallic compounds are combined together with aluminum substrate.Have The progress for preventing abrasion of effect so that wear extent is less.After 10min, with the progress of abrasion, contact area increase, composite wood The rate of depreciation increase of material.But from the slope of one time diagram of weight loss of fretting wear, rate of depreciation is basicly stable.Due to Processing hardening occurs due to plastic deformation for the surface of sample, improves wearability；And Mg₂Si is entirely incorporated in one with aluminum substrate It rises, the phenomenon that not falling off, therefore, rate of depreciation is maintained at a stable scope.

Case study on implementation 4：

In frictional wear experiment, since A1 is face-centred cubic structure, plasticity is big, and wearability is poor, and the abrasive dust of fine aluminium is shelled in banding Fall.Containing 5%Mg₂The composite material abrasive dust of Si is in the form of sheets, it can be seen that and the surface after abrasion is tear shape, there is seldom ploughing phenomena, Wear extent is very big.This is because due to Mg₂Si contents are seldom, not big enough to the humidification of the composite material, in shearing force Under effect, enhancing is mutually peeled off together with matrix, and so as to form hole and torn grain, wear mechanism at this time is mainly worn with removing Based on and be aided with slight abrasive wear.With the enhancing of enhancing granule content, the wearability enhancing of composite material, containing 8% Mg₂In the composite material of Si.Its abrasive dust is in smaller sheet or larger granulated powder.What wearability behaved oneself best is to contain 10%Mg₂The composite material of Si, abrasive dust are in powdered, and the surface parallel scratches after abrasion are shallower, and ditch dug with a plow is less, even wearing, are belonged to In overall wear, wear extent is minimum, and wear mechanism at this time is mainly based on abrasive wear.

Case study on implementation 5：

Mg₂There are two the stages for the one in-fighting figure of strain of Si/Al in-situ composites.In-fighting increases with strain and is dropped in first stage It is low.It at this time can be there are one minimum value.This minimum value can preferably reaction material damping and amortization；In second stage, in-fighting meeting Increase with the increase of strain, generated certain plastic deformation at this time.The dislocation of material internal in itself is by sliding or climbing The other modes such as shifting multiplication, this can greatly increase the damping and amortization of material but arrive to a certain degree, and dislocation can keep a balance Scope, damping value at this time can be also in a horizontal extent.Therefore, to measure Mg₂The resistance of Si/Al composite materials in itself Buddhist nun's property takes the first stage of one in-fighting figure of strain, i.e. material minimum damping value in this experiment.It is prepared by stirring casting method Mg₂Si/Al in-situ composite damping and amortizations are significantly improved, wherein, Mg₂When Si contents are 10%, the enhancing of in-fighting highest 9.85 times.This is because this experimental temperature is higher.Generate the intermetallic compound Mg of high damping₂Si.This enhancing Grain can preferably inhibit the propagation of energy.Enhancing phase Mg in composite material₂Si makees in strong stirring shearing and collision Under, particle is tiny, is uniformly dispersed, these tiny grain pining growths in matrix, energy in the composite communication process when, It must bypass them.So cause the attenuation of energy.Further, since temperature gradient, churned mechanically shear action during solidification Etc. causing the uneven forming core of crystal.And nucleation rate increases, the crystal grain and matrix grain for enhancing phase produce during growth A large amount of dislocations have been given birth to, have played the role of very heavy damping to the transmission of energy.Second in the composite material meets generates boundary with matrix Face.Due to the effect of thermal stress and structural stress, it may appear that the phenomenon that stress concentration.When stress up to occurs the regional area During sliding, a large amount of dislocations can be also generated, hinder energy transmission.Therefore, Mg₂Si/Al in-situ composites have damping well Property.

Claims

1. a kind of fabricated in situ Mg₂Si/Al composite materials, preparing raw material includes：Matrix is commercial-purity aluminium, and reinforcement is silica flour (75 μm) and AZ31D magnesium alloys react at high temperature generation Mg₂Si。

2. fabricated in situ Mg according to claim 1₂Si/Al composite materials, it is characterized in that fabricated in situ Mg₂Si/Al is compound The preparation process of material is：Resistance furnace is first warming up to 720 DEG C, aluminium ingot is put into crucible；Molten aluminum is superheated to 870 DEG C, is added Enter the silica flour through 200 DEG C of pretreatment 2h：Adds in AZ31D magnesium alloys using the stirring of homemade three leaves blender after 5min, allows Si It is fully reacted with Mg；After stirring 10min, cast molding.

3. fabricated in situ Mg according to claim 1₂Si/Al composite materials, it is characterized in that fabricated in situ Mg₂Si/Al is compound The detecting step of material is：The material phase analysis of composite material is carried out using D8-ADVANCE types X-ray diffractometer；Use JSM- Enhance size, pattern and the distribution of particle in 6360LA type scanning electron microscopic observation composite material microscopic structures；It will be cast by stirring Make the Mg of preparation₂Be processed into respectively on Si/Al in-situ composite cutting on line machines 10mmX10mmX15mm, The sample of 7mmX7mmX30mm, 40mmX5mmX1mm are polished smooth surface with sand paper；XHV-1000 types are respectively adopted from turn Tower digital display microhardness testers, M-2000 types friction and wear tester, TPA-8 type precisions rock mechanical spectrometer test compound material Microhardness；To ensure the accuracy of data, four different points are chosen on each sample and carry out hardness test, are averaged Value；Wearability experiment power is 400N, rotating speed 180r/min；After before experiment sample is cleaned, dry, using SHIMA- DZUAUY220 type electronic balance weighings, place into experimental machine wear cleaning after 5min, it is dry weigh, 4 times repeatedly；Damping and amortization Experimental temperature is 30.8 DEG C, setpoint frequency 1.000Hz.

4. fabricated in situ Mg according to claim 1₂Si/Al composite materials, it is characterized in that casting legal system by mechanical agitation For Mg₂Si/Al in-situ composites, Mg₂White dendroid, the enhancing tiny of particle are evenly distributed on Si in the composite In matrix, enhancing phase and the interface cleanness of matrix are pollution-free；Si and Mg reactions completely generate Mg₂Si, a small amount of Mg are also anti-with Al Mg should be generated_l7Al_l2, micro Mg is present in solid solution thereof in composite material；Mg₂The microhardness of Si/Al composite materials, Wearability and damping and amortization are improved, wherein Mg₂When Si contents are lO%, which carries with respect to the microhardness of fine aluminium 1.71 times high, wearability improves 2.42 times, and Internal friction improves 9.85 times.