magnesium alloy

摘要： The linear shaped charge cutting technology is an effective technology for aircraft separation.It can separate invalid components from aircrafts timely to achieve light-weight.Magnesium alloy is the lightest metal material,and can be used to cast effective light-weight components of an aircraft construction.However,the application study of the linear shaped charge cutting technology on magnesium alloy components is basically blank.In response to the demand for the linear separation of magnesium alloys,the Mg-12Gd-0.5Y-0.4Zn alloy is selected to carry out the target shaped charge cutting test.The effects of the shaped charge line density,cutting thickness,and mechanical properties on the cutting performance of the alloy are studied.The shaped charge cutting mechanism is analyzed through the notch structure.The results show that the linear shaped charge cutting performance is significantly affected by the penetration and the collapse.The higher the linear density is,the stronger the ability of the linear shaped charge cutter is,and the greater the penetration depth is,which is advantageous.However,the target structure will be damaged when it is too large(e.g.,4.5 g·m^(-1)).Within 12 mm,when the cutting thickness of the target increases,the penetration depth increases.The lower the tensile strength is,the greater the penetration depth is,and the more conducive the penetration depth to the shaped charge cutting is.When the elongation(EL)increases to 12%,the collapse of the target is incomplete and the target cannot be separated.When the tensile strength of the Mg-Gd-Y-Zn alloy is less than 350 MPa,the EL is less than 6.5%,the cutting thickness is less than 12 mm,and the linear shaped charge cutting of the magnesium alloy can be achieved stably.

摘要： Owing to the nonuniform wall thickness and complex internal structure,the measurement of the residual stress on magnesium alloy cabin castings is complex and difficult extremely,and thus seldom research has focused on the residual stress of magnesium alloy castings.In this paper,the blind-hole method,the X-ray diffraction(XRD)method,and the contour method are used to conduct comprehensive and systematic residual stress tests for a magnesium alloy cabin casting.The results show that the residual stress on the surface of the casting obtained by the blind-hole method is between-20.03 MPa and-71.03 MPa,the residual stress obtained by the XRD method is between-26.01 MPa and-87.11 MPa,while the residual stress obtained by the contour method is between-45.89 MPa and 76.87 MPa.The study can lay a basis for the subsequent research of magnesium alloy cabin castings,and provide a reference for the residual stress test of magnesium alloy castings.

摘要： Magnesium alloys are well applied in aerospace and aviation because of their mass saving potential,good electromagnetic shielding performance,and high damping capacity. To further promote the applications,in this paper,the applications of magnesium alloys are reviewed,which could provide insights for researchers and application designers. Firstly,the applications in aerospace are reviewed,including missile,satellite,rocket,and spacecraft.Secondly,the applications and commercial magnesium alloys in aviation are summarized. Thirdly,the bottleneck and existing problems for such magnesium alloys applied in aerospace and aviation are discussed. The requirements for the magnesium alloy performance in aerospace and aviation are evaluated and elaborated.

摘要： Using Gleeble-3500 thermal simulator,the high temperature plastic deformation behavior and microstructure evolution of Mg-9Al-3Si-0.375Sr-0.78Y alloy are investigated at the temperature of 523 K?673 K and the strain rate of 10^(-3)s^(-1) 10 s^(-1).True strain-true stress curves show the characteristics of the typical dynamically recrystallization process.The Arrhenius constitutive equation of the hyperbolic model is established.The average activation energy and the strain rate sensitivity index are,respectively,221.578 kJ·mol^(-1) and 0.137.The result shows that theα-Mg phase exhibits dynamic recrystallization (DRX)characteristics obviously.But no DRX occurs in the β-Mg_(17)Al_(12) phase.Hot deformation does not affect the primary Mg_(2)Si phase.Under the conditions of low temperature (523 K?673 K) and high strain rate(1 s^(-1) 10 s^(-1)),the flow instability and macro-defects such as crack appear in the specimens.However,there are finer recrystallization grains.Under the conditions of high temperature(≥673 K)or low strain rate,the microstructure of the alloy shows good homogeneity.The size of the primary Mg_(2)Si phase is uniform,the size of the β-Mg_(17)Al_(12) phase is small,and the distribution of the β-Mg_(17)Al_(12) phase is uniform.

摘要： Bending and tension deformations were performed on Mg-1.3 wt%Zn-0.2 wt%RE-0.3 wt%Zr(ZEK100)alloy sheets that initially had a transverse direction(TD)-split texture.The effects of bending and tension deformations on the texture formation and room-temperature formability of specimens were investigated.The specimen subjected to 3-pass bending and tension deformations exhibited an excellent Erichsen value of 9.6 mm.However,the Erichsen value deterioration was observed in the specimen subjected to 7-pass deformations.The rolling direction-split texture developed on the surface with an increasing pass number of deformations.Conversely,the clear TD-split texture remained at the central part.As a result,a quadrupole texture was macroscopically developed with an increasing pass number of deformations.The reduction in anisotropy by the formation of the quadrupole texture is suggested to be the main reason for the improvement in stretch formability.By contrast,the generation of coarse grains near the surface is suggested to be the direct cause for the deterioration of the stretch formability of the specimen subjected to 7-pass deformations.

摘要： A significant enhancement of bendability was achieved by the introduction of bimodal microstructure for AZ31B alloy sheets via pre-compression and subsequent annealing(PCA)process.This combined treatment led to the c-axis of the extracted samples that were inclined by 30°to the rolling direction(30°sample)further shifting toward the rolling direction(RD)and resulting in a higher Schmid factor(SF)value of basal slip under the RD tensile stress.Furthermore,the bimodal microstructure that was introduced by the PCA process broke the damage bands(DBs)in the initial hot rolled AZ31B alloy sheets and gave rise to a more uniform strain distribution in the outer tension region of the bending samples,in which the tensile deformation was accommodated by the equally distributed{101^(-)2}tension twinning and basal slip.Consequently,the bimodal microstructure,shifted basal texture and the modification of DBs were responsible for the significant enhancement in the bendability of the AZ31 alloys.

摘要： Although graphene oxide(GO)has emerged as an excellent lubricant additive in water,there remain great challenges in their practical application due to high production costs.By taking into account the low cost and also its excellent tribological properties,it is likely that nano-SiO_(2)can be used as a lubricant additive to partially replace GO.Hence,this paper aims to explore the tribological properties of nano-SiO_(2)incorporated in GO nanofluids for partial GO replacement by investigating the friction coefficient and wear volume of the prepared SiO_(2)/GO hybrid nanofluids for magnesium alloy/steel sliding pairs.The experiments reveal that the SiO_(2)/GO hybrids retain low friction coefficients as compared to individual GO or SiO_(2)at all test conditions in this study.However,as for the bearing capacity test,all samples can provide a low wear volume under the loads of 1 and 3 N.With the increase of the normal load,there is considerable differences in the anti-wear behavior.Compared with that of individual GO nanofluids,the wear volume of the GO/SiO_(2)(mass ratio of 0.3:0.2)hybrid nanofluids was reduced by50.5%at 5 N and by 49.2%at 8 N.Furthermore,the wear volume of the GO/SiO_(2)(mass ratio of 0.3:0.2)hybrid nanofluids was reduced by46.3%under the rigorous conditions,as compared to individual GO nanofluids.The findings provide new insights into developing carbon nanomaterial-based hybrid nanofluids for magnesium alloy formation.

摘要： Large plastic deformation commonly occurs during the practical forming process in industries.Compared with uniaxial tension/compression,torsion is a more effective approach to investigate mechanical behavior under large deformation.The response of the large strain torsion of magnesium alloy is sensitive to the initial texture and twinning.Therefore,an extruded AZ31 alloy was pre-stressed in tension and compression to introduce dislocations and twins in the current work.Subsequently,torsion tests were conducted to clarify the effects of twinning and dislocation on subsequent deformation responses.The corresponding microstructure and deformation mechanisms were explored on the basis of viscoplastic self-consistent(VPSC)modeling.The experimental observations on stress-strain responses and pole figures were captured by simulation work.It was found that twins make less contribution to plastic deformation,which results in small change in texture direction under pure torsion and torsion after pretension.The activity of the slip/twin system and the mechanical properties are affected by different initial textures and active conditions of the system.Moreover,the stress state during combined tension-torsion loading benefits the reduction of texture intensity.

摘要： The microstructure evolution and age-hardening response for different Sm/Sn ratios(0-2.55,in wt.%)of Mg-Sn-Sm alloys were investigated.The second phase formation in as-cast alloys and the Mg_(3)Sm precipitates formed in aged alloys were characterized using XRD,FESEM and HAADF-STEM with EDS techniques.Results indicate that the Sm/Sn ratio has a great influence on the phase constitution,α-Mg grain size and age-hardening response.With the increment of Sm/Sn ratio,Mg_(41)Sm_(5) and thermally stable MgSnSm phases precipitate.When the Sm/Sn ratio is about 1.19,the secondary dendrite arm spacing ofα-Mg grains significantly decreases.Furthermore,the alloy with Sm/Sn ratio up to 2.55 exhibits the highest age-hardening response,the hardness value increases from 52 HB at solution-treated condition to 74 HB at peak-aged condition(ageing at 220 °C for a short time of 4 h).This is attributed to the large volume fraction of needle-like Mg_(3)Sm precipitates formed in theα-Mg matrix during ageing treatment,which results in a significant precipitation strengthening effect.

摘要： The characteristics of defect bands in the microstructure of high pressure die casting(HPDC)AE44 magnesium alloy were investigated.Special attention was paid to the effects of process parameters during the HPDC process and casting structure on the distribution of defect bands.Results show that the defect bands are solute segregation bands with the enrichment of Al,Ce and La elements,which are basically in the form of Al_(11)RE_(3) phase.There is no obvious aggregation of porosities in the defect bands.The width of the inner defect band is 4-8 times larger than that of the outer one.The variation trends of the distribution of the inner and outer defect bands are not consistent under different process parameters and at different locations of castings.This is due to the discrepancy between the formation mechanisms of double defect bands.The filling and solidification behavior of the melt near the chilling layer is very complicated,which finally leads to a fluctuation of the width and location of the outer defect band.By affecting the content and aggregation degree of externally solidified crystals(ESCs)in the cross section of die castings,the process parameters and casting structure have a great influence on the distribution of the inner defect band.

摘要： The corrosion and high-temperature oxidation characteristics of AM60 magnesium alloys in different environments were investigated by means of immersion test，electrochemical polarizing analysis and DTA/TG experiments. The influence of aging heat treatment on the corrosion resistance of AM60 magnesium alloys has been studied in details. It showed better corrosion resistance in sea water than in 3.5wt％ NaCl solution. The corrosion resistance after aging 24h was better than that of both as-cast and aging 48h ones. Corrosion resistance of Mg Alloy is controlled by microstructure，composition of αmatrix. Precipitation of βphase along the grain boundaries acts as a barrier which decrease corrosion rate，while the decrease of aluminum content of α causing an increase in the corrosion rate. The DTA and TG curves of heating process in air are characterized with combustion after 590°C. While heating in helium，the curves show two endothermal peaks and a remarkable evaporation of magnesium. Are different each other for AM60 heated in air and helium atmosphere. As for isothermal DTA and TG experiment，weight increment does happen till 520°C which results from oxidation.

摘要： The corrosion and high-temperature oxidation characteristics of AM60 magnesium alloys in different environments were investigated by means of immersion test，electrochemical polarizing analysis and DTA/TG experiments. The influence of aging heat treatment on the corrosion resistance of AM60 magnesium alloys has been studied in details. It showed better corrosion resistance in sea water than in 3.5wt％ NaCl solution. The corrosion resistance after aging 24h was better than that of both as-cast and aging 48h ones. Corrosion resistance of Mg Alloy is controlled by microstructure，composition of αmatrix. Precipitation of βphase along the grain boundaries acts as a barrier which decrease corrosion rate，while the decrease of aluminum content of α causing an increase in the corrosion rate. The DTA and TG curves of heating process in air are characterized with combustion after 590°C. While heating in helium，the curves show two endothermal peaks and a remarkable evaporation of magnesium. Are different each other for AM60 heated in air and helium atmosphere. As for isothermal DTA and TG experiment，weight increment does happen till 520°C which results from oxidation.

摘要： The corrosion and high-temperature oxidation characteristics of AM60 magnesium alloys in different environments were investigated by means of immersion test，electrochemical polarizing analysis and DTA/TG experiments. The influence of aging heat treatment on the corrosion resistance of AM60 magnesium alloys has been studied in details. It showed better corrosion resistance in sea water than in 3.5wt％ NaCl solution. The corrosion resistance after aging 24h was better than that of both as-cast and aging 48h ones. Corrosion resistance of Mg Alloy is controlled by microstructure，composition of αmatrix. Precipitation of βphase along the grain boundaries acts as a barrier which decrease corrosion rate，while the decrease of aluminum content of α causing an increase in the corrosion rate. The DTA and TG curves of heating process in air are characterized with combustion after 590°C. While heating in helium，the curves show two endothermal peaks and a remarkable evaporation of magnesium. Are different each other for AM60 heated in air and helium atmosphere. As for isothermal DTA and TG experiment，weight increment does happen till 520°C which results from oxidation.

摘要： The corrosion and high-temperature oxidation characteristics of AM60 magnesium alloys in different environments were investigated by means of immersion test，electrochemical polarizing analysis and DTA/TG experiments. The influence of aging heat treatment on the corrosion resistance of AM60 magnesium alloys has been studied in details. It showed better corrosion resistance in sea water than in 3.5wt％ NaCl solution. The corrosion resistance after aging 24h was better than that of both as-cast and aging 48h ones. Corrosion resistance of Mg Alloy is controlled by microstructure，composition of αmatrix. Precipitation of βphase along the grain boundaries acts as a barrier which decrease corrosion rate，while the decrease of aluminum content of α causing an increase in the corrosion rate. The DTA and TG curves of heating process in air are characterized with combustion after 590°C. While heating in helium，the curves show two endothermal peaks and a remarkable evaporation of magnesium. Are different each other for AM60 heated in air and helium atmosphere. As for isothermal DTA and TG experiment，weight increment does happen till 520°C which results from oxidation.

摘要： The corrosion and high-temperature oxidation characteristics of AM60 magnesium alloys in different environments were investigated by means of immersion test，electrochemical polarizing analysis and DTA/TG experiments. The influence of aging heat treatment on the corrosion resistance of AM60 magnesium alloys has been studied in details. It showed better corrosion resistance in sea water than in 3.5wt％ NaCl solution. The corrosion resistance after aging 24h was better than that of both as-cast and aging 48h ones. Corrosion resistance of Mg Alloy is controlled by microstructure，composition of αmatrix. Precipitation of βphase along the grain boundaries acts as a barrier which decrease corrosion rate，while the decrease of aluminum content of α causing an increase in the corrosion rate. The DTA and TG curves of heating process in air are characterized with combustion after 590°C. While heating in helium，the curves show two endothermal peaks and a remarkable evaporation of magnesium. Are different each other for AM60 heated in air and helium atmosphere. As for isothermal DTA and TG experiment，weight increment does happen till 520°C which results from oxidation.

摘要： The corrosion and high-temperature oxidation characteristics of AM60 magnesium alloys in different environments were investigated by means of immersion test，electrochemical polarizing analysis and DTA/TG experiments. The influence of aging heat treatment on the corrosion resistance of AM60 magnesium alloys has been studied in details. It showed better corrosion resistance in sea water than in 3.5wt％ NaCl solution. The corrosion resistance after aging 24h was better than that of both as-cast and aging 48h ones. Corrosion resistance of Mg Alloy is controlled by microstructure，composition of αmatrix. Precipitation of βphase along the grain boundaries acts as a barrier which decrease corrosion rate，while the decrease of aluminum content of α causing an increase in the corrosion rate. The DTA and TG curves of heating process in air are characterized with combustion after 590°C. While heating in helium，the curves show two endothermal peaks and a remarkable evaporation of magnesium. Are different each other for AM60 heated in air and helium atmosphere. As for isothermal DTA and TG experiment，weight increment does happen till 520°C which results from oxidation.

摘要： A series high temperature creep resistance magnesium alloy for die casting based on AZ91 was successful developed by addition of Rare Earth, and Calcium. The original target of magnesium alloy development was aimed at cylinder head cover of high power diesel engine, and tried to satisfy the temperature demands of gear-box house. The tensile property at room temperature, creep behavior at 150 °C , and analysis of microstructure was discussed in this paper. The results show that the series high temperature creep resistance magnesium alloy for die casting has potential to produce power-train parts, and greatly decrease the weigh of parts.

摘要： A series high temperature creep resistance magnesium alloy for die casting based on AZ91 was successful developed by addition of Rare Earth, and Calcium. The original target of magnesium alloy development was aimed at cylinder head cover of high power diesel engine, and tried to satisfy the temperature demands of gear-box house. The tensile property at room temperature, creep behavior at 150 °C , and analysis of microstructure was discussed in this paper. The results show that the series high temperature creep resistance magnesium alloy for die casting has potential to produce power-train parts, and greatly decrease the weigh of parts.

摘要： A series high temperature creep resistance magnesium alloy for die casting based on AZ91 was successful developed by addition of Rare Earth, and Calcium. The original target of magnesium alloy development was aimed at cylinder head cover of high power diesel engine, and tried to satisfy the temperature demands of gear-box house. The tensile property at room temperature, creep behavior at 150 °C , and analysis of microstructure was discussed in this paper. The results show that the series high temperature creep resistance magnesium alloy for die casting has potential to produce power-train parts, and greatly decrease the weigh of parts.

摘要： A series high temperature creep resistance magnesium alloy for die casting based on AZ91 was successful developed by addition of Rare Earth, and Calcium. The original target of magnesium alloy development was aimed at cylinder head cover of high power diesel engine, and tried to satisfy the temperature demands of gear-box house. The tensile property at room temperature, creep behavior at 150 °C , and analysis of microstructure was discussed in this paper. The results show that the series high temperature creep resistance magnesium alloy for die casting has potential to produce power-train parts, and greatly decrease the weigh of parts.