Intermetallic Compound Mg17Al12 Research Articles

Research on the interfacial microstructure and mechanical properties of glass/Mg joint prepared by anodic bonding and vacuum diffusion bonding

The joining of glass and Mg by a combination of anodic bonding and vacuum diffusion bonding with Al as the interlayer was achieved in one step. The microstructures of glass/Mg dissimilar joints were analyzed using optical microscopy, SEM, and EDS. The results show that the bonding interface was joined well without any voids and cracks. Na+ and Ca2+ depletion regions would be produced in the glass near the Al foil, where the width of the Na+ depletion region was larger than that of the Ca2+ depletion region. In addition, the content of Al element in the depletion regions increased, and the diffusion of Al into the depletion regions was responsible for the successful glass/Al bonding process. Al3Mg2 and Al12Mg17 intermetallic compound (IMC) layers were formed between the Al and Mg. The anodic bonding process and the vacuum diffusion bonding process were independent of each other: and the thickness of the IMC layer increased with the increase of the diffusion bonding time, while the width of the Na+, Ca2+ depletion region remained constant; Meanwhile, the variation of the anodic bonding parameters only affected the width of the depletion layer and had no effect on the thickness of the Al3Mg2 and the Al12Mg17 IMC layer. The fracture position of the sample changed from the Al/Mg bonding interface to the glass/Al bonding interface as the thickness of the IMC layer increased. The maximum tensile strength of 14.6 MPa was obtained by vacuum diffusion bonding at 450 °C for 20 min and anodic bonding under 400 °C and 800 V.

Experimental and numerical simulation study of magnesium/aluminium dissimilar metal swing laser welding

In this study, AZ91/6061 joint were successfully prepared by using the swing laser welding process, and the process, microstructure, mechanical properties, and temperature field distribution of swing laser welding were investigated. During welding, the laser beam is always in the transverse swing state, which has a stirring effect on the liquid molten pool, optimizing the size and distribution of Mg-Al intermetallic compounds in the weld, forming mechanical interlocking structure, which is beneficial to reducing the hazardous effects of intermetallic compounds on the joint properties. The microstructure results show that the Mg/Al reaction interface mainly consists of (α-Mg+Al12Mg17) eutectic structure, and Al12Mg17, and the different compounds form a wave-shaped mechanical interlocking structure. Orthogonal test results show that the laser power has the greatest influence on the joint performance, when the laser power is 900 W, the shear strength of the joint is 40.72 MPa, the fracture occurs in the mechanical interlocking zone, and the fracture mode is brittle fracture. In this case, the strengthening mechanism is the mechanical interlocking structure that prevents crack extension and the stirring effect of the swing laser beam on the liquid molten pool that avoids the formation of continuously distributed bulk Mg-Al intermetallic compounds. Numerical simulation results show that the centre zone of the heat source moves from side to side with the swing of the laser beam, resulting in a more uniform temperature distribution in the joint.

Development of prominent bonding strength in Al/Mg bimetal composites prepared by ultrasonic vibration-assisted compound casting: Effects of ultrasonic powers

In this work, the A356/AZ91D bimetal composites were prepared by ultrasonic vibration-assisted lost foam compound casting, and the effects of ultrasonic powers on interfacial microstructures and mechanical properties of the Al/Mg interfaces were investigated. Results revealed that the Al/Mg bimetal composites without ultrasonic vibration treatment (UVT) were heterogeneous, and the Al/Mg interface was composed of Al-Mg intermetallic compounds (IMCs, i.e., Al3Mg2 and Al12Mg17) area and Al-Mg eutectic structures (δ-Mg+Al12Mg17) area. The Mg2Si particles were gathered at the IMCs area and an oxide film that mainly composed of Al2O3 was existed between the IMCs area and eutectic structures area. With UVT, the oxide film was eliminated and the gathered Mg2Si particles were refined and dispersed by the acoustic cavitation effect, and part of the Al3Mg2 and Al-Mg eutectic structures were transformed into the Al12Mg17 due to the promoted solute interdiffusion, which improved the homogeneity of the Al/Mg interfaces. Besides, the grains of the Al/Mg interface with UVT under ultrasonic power of 75 W were significantly refined. The thickness of Al/Mg interface was increased with the increase of the ultrasonic power. Due to the excessive heat induced by UVT under the further increased ultrasonic power, the cooling rates and the degree of supercooling were reduced, resulting in the coarsening of interfacial grains. The microhardness of the Al/Mg interfaces was increased and got more uniform by UVT. The shear strengths of the Al/Mg bimetal composites with UVT were enhanced to 61.4 MPa from 32.4 MPa, with an increase of 89.5 % compared with that of the Al/Mg bimetal without UVT. This could be ascribed to the removal of the oxide film, the refinement of the interfacial grains and the dispersed and refined Mg2Si particles achieved by UVT, which hindered the crack propagation during deformation.

Effect of nanoparticles adhesion and multipass friction stir processing on metallurgical properties of AZ91D magnesium alloy

In this work, the effect of SiC and Al2O3 nanoparticles and multipass friction stir processing (MPFSP) on the metallurgical properties of AZ91D was carefully investigated and observed a homogenous dispersion of nanoparticles and refined grain size in the processed zone. The presence of the Mg17Al12 intermetallic compound in the MPFSP of AZ91D with SiC and Al2O3 nanoparticles has significant implications for the material’s properties. Mg17Al12 is a typical intermetallic phase formed in magnesium alloys and can profoundly affect thermal, microstructural, and mechanical properties. The intermetallic phase can improve the processed region’s strength due to its inherent hardness and solid solution strengthening effect, resulting in enhanced tensile properties and hardness. As the FSP passes increased, the tendency for reinforcement agglomeration diminished. Before undergoing MPFSP/(SiC + Al2O3), the base metal AZ91D exhibited an ultimate tensile strength (UTS) of 208.36 MPa and a strain percentage 15.72. After implementing MPFSP/(SiC and Al2O3) on AZ91D, the UTS consistently increased with each FSP pass. This effect was evident at the fourth FSP pass, yielding a higher UTS of 284.35 MPa. In essence, this process facilitated a marked enhancement in the metallurgical properties of AZ91D, signifying the efficacy of the MPFSP approach when combined with reinforcement particles. The hardness value was higher when the indenter engaged with Mg17Al12 than α-Mg. The SZ of 4-pass FSP (Al2O3+SiC)/AZ91D reached a maximum hardness value of 69.37 HV, while single-pass FSP (Al2O3)/AZ91D exhibited a minimum value of 64.89 HV.

X-ray tomography and characterization of dissimilar interface revealing the interplay of intermetallics, interlocking, and voids on joint strength of Al6061 and AZ31Mg dissimilar friction stir welds

This work focuses on the analysis of the combined effect of intermetallic, interlocking, and voids on the joint strength of Al6061 and AZ31 Mg dissimilar friction stir welds. The FSW of Al6061 and AZ31 Mg is performed with different tool rotation speeds and feed rates. Tensile test specimens are prepared from these joints and subjected to X-ray tomography, which reveals the serrations and voids at the Al6061/AZ31 interface. Here, Serrations interlock the materials and increase the interface area. Serrations pitch is higher in shoulder driven region (1.4 – 0.6 mm) compared to pin driven region (0.5 – 0.2 mm). The Al6061 and AZ31 Mg interface is also accompanied by voids, where void fraction is around 0 % near the top and 2–7 % near the bottom. SEM, EDS mapping, and XRD 2-theta scans of the Al6061/AZ31 Mg interface are utilized to investigate the intermetallic compounds. Al3Mg2 and Al12Mg17 intermetallic compounds are observed at Al6061/AZ31 Mg interface. Further, the intermetallic compound thickness increases from 2.8μm to 5.3 μm with increase tool rotational speed from 500 rpm to 800 rpm. Based on the variation of joint strength against these parameters, the intermetallic compound thickness is the most detrimental contributor to the joint strength, followed by void volume and interface area, for the Al6061 and AZ31 Mg dissimilar joints. The maximum joint strength of 112.1 MPa is achieved, which is 40 % and 33 % of AZ31 Mg and Al6061, respectively.

Joining mechanism, microstructure, and mechanical properties of AZ31/6061 joint prepared by pouring fusion welding process assisted with Zn-xSn brazing filler

In this study, AZ31/6061 dissimilar metal joints were manufactured using pouring fusion welding assisted with Zn-xSn brazing filler, and the process, microstructure and mechanical properties of Mg/Al joint were investigated. During welding, the addition of molten Zn-xSn brazing filler completely isolates the direct contact of Mg/Al, preventing the formation of Mg-Al intermetallic compounds. As the Sn content changes, the microstructure of the joints also changes. When the Sn content is 25 wt.%, the microstructure of the AZ31 side is dominated by Mg-Al-Zn ternary eutectic structure, Al6Mg11Zn11, (β-Zn + MgZn2), Al-Zn-Sn (SS), Sn (SS) and Mg2Sn. And the microstructure of the 6061 side is dominated by Al-Zn-Sn (SS), β-Zn, Al-Zn-Sn (SS), and Sn (SS). The width of the Mg-Al-Zn ternary eutectic structure layer decreases with the increase of Sn content. In addition, high Sn content and high heat input promote the formation of Mg2Sn, and large amounts of Mg2Sn are generated with Zn-40Sn interlayer. The average microhardness of the joint gradually decreases with the increase of Sn content. However, the shear strength of the joint first increases and then decreases, and the shear strength of the joint with the Zn-25Sn interlayer is the highest, which is 50.60 MPa. Fracture mode is cleavage fracture.

On the microstructure and texture of intermetallics in Al/Mg/Al multi-layer composite fabricated by Accumulative Roll Bonding

The microstructure and texture of the intermetallics in Al/Mg/Al multi-layer composite fabricated by Accumulative Roll Bonding (ARB) at 400 °C up to 6 cycles were investigated using Electron BackScatter Diffraction (EBSD) and Synchrotron X-ray Diffraction (SXRD). EBSD and SXRD analysis have shown that ARB processing leads to the formation of Al3Mg2 and Mg17Al12 intermetallics soon after the second ARB cycle with a global thickness of 12 (N = 2) to 22 µm (N = 6). The polycrystalline intermetallics plates growth was columnar and normal to the bonding interface. A constitutional liquefaction region was depicted ahead of the plates with an unusual rugged migration front. The Al3Mg2 and Mg17Al12 intermetallic compounds which formed after 2 ARB cycles have approximately the same average grain size (1.0 µm) at this cycle. After 4 ARB cycles, the grain refinement of Al3Mg2 is more than 4 times higher than in Mg17Al12. The average grain size of Al3Mg2 and Mg17Al12 reach 0.2 and 0.9 µm, respectively. After 6 cycles of ARB, the average grain size of both Al3Mg2 and Mg17Al12 increased to 1.5 µm and 2.8 µm, respectively. The dislocation density obeyed a ρAl3Mg2 > ρAZ31 > ρAl 1050 ∼ ρMg17Al12 hierarchy after N = 4 and 6 ARB cycles and the Al3Mg2 was shown to store more dislocations. Through the ARB processing, a usual strong basal (0002) texture was depicted in AZ31 layers and a weak rolling texture was shown in Al 1050 layers with a dominant Rotated Cube (001) 110 > component that vanished after upon increasing ARB cycles. The Al3Mg2 and Mg17Al12 intermetallics were characterized by a random texture.

Interfacial Microstructure Evaluation of Precisely Controlled Friction Stir Welding Joints of Al/Mg Dissimilar Alloys with Zn Interlayer

In this study, a penetration-controlled friction stir welding (FSW) technique was employed to lap weld dissimilar Al/Mg alloys, incorporating a Zn interlayer. The joint’s microstructure, interfacial reaction, and phase composition were analyzed through optical microscopy, scanning electron microscopy, and X-ray diffraction. The findings demonstrate the formation of a hybrid joint comprising a FSWed region and a diffusion bonding region achieved by introducing a pure Zn interlayer at the Al/Mg interface. Within the FSWed region, the zinc was fully extruded, leading to favorable interface bonding. In contrast, the diffusion bonding region exhibited an aluminum–zinc diffusion reaction layer, an incompletely reacted zinc layer, and a zinc–magnesium diffusion reaction layer. Notably, no Al-Mg intermetallic compounds (IMCs) were observed in either the FSWed or diffusion bonding regions of the hybrid joint. This study further explored the underlying mechanism behind the joint’s formation.

Improved mechanical and corrosion properties of friction stir welded Al/Mg dissimilar lap joints by Zr interlayer addition

The effect of Zr interlayer on the degradation rate in mechanical strength of friction stir welded 6061 Al/AZ31 Mg dissimilar lap joints during corrosion was investigated. The layer thickness of detrimental Al-Mg intermetallic compounds was reduced by the Zr interlayer. The immersion corrosion tests indicated that the Zr interlayer enhanced the corrosion resistance of Al/Mg joint by mitigating the galvanic corrosion at the lap interface to exhibit a 12% reduction in the weight loss for the Al/Zr/Mg joint. The tensile shear tests suggested that a higher residual mechanical strength was obtained for the Al/Zr/Mg joint compared with that of the Al/Mg joint, whose strength loss ratio was decreased from 86% to 67% after adding the Zr interlayer.

The Effect of Ti Particles Addition on the Microstructure and Mechanical Behavior of Mg AZ31/Al 6082 Composite Sheets

In this study, Ti particles reinforced Mg AZ31/Al 6082 composite sheets were successfully prepared by hot rolling, with the aim of revealing the effect of Ti particles addition on the mechanical behavior and microstructure of Mg AZ31/Al 6082 composite sheets. The results showed that Ti particles were uniformly distributed at the interface of the Mg/Al-Ti composite sheets, which could greatly reduce the amount of Mg-Al intermetallic compounds during annealing treatment. Compared to the Mg/Al sheet, the tensile strength and elongation of the Mg/Al-Ti sheet could be improved simultaneously after the annealing treatment. Ti particles addition hardly affected the grain size, texture type, and tensile fracture morphology of the Mg layer and Al layer in the composite sheets before and after annealing. This present study provides a new perspective on the mechanical behavior and microstructure of Mg/Al composites through the addition of metal particles.

Study on TIG Process of AZ31 Magnesium Alloy

In this paper, manual argon tungsten arc welding is used to weld AZ31 magnesium alloy plate with thickness of 2.5mm on both sides. The welding current parameters are changed. The best welding current is explored by analyzing the performance of welding joint; The corrosion resistance of welded joint was studied in the same medium. The results show that the microstructure of base metal zone is α- Mg solid solution, and the microstructure of the weld seam is mg solid solution α- Mg solid solution and β- Mg17Al12 intermetallic compound. When the welding current increases from 80A to 120A, the welding heat input increases gradually, and the grain size of HAZ increases gradually. The results of microhardness test show that the microhardness of weld zone is the largest, that of base metal is moderate, and that of heat affected zone is the lowest. The corrosion resistance of AZ31 magnesium alloy welded joint shows that the corrosion resistance of the weld zone is better than that of the base metal zone.

The joining of magnesium and aluminium alloys by inclined arrangement of explosive welding

Multi-material lightweight frames are growing rapidly in a variety of industries, specifically where weight reduction, performance improvement, and cost savings are required. Magnesium alloys (AZ31B) fulfil the requirements, but they are prone to corrosion. The joining of magnesium and aluminium alloys is being suggested as an effective approach to this issue.In this study, aluminium alloy and magnesium alloy plates were joined successfully through the inclined arrangement of the explosive welding method. The interface microstructure and mechanical properties of joined plates were examined. The microstructural studies illustrated the development of a wavy interface with the Al12Mg17 intermetallic compound. The maximum microhardness values were obtained close to the interface due to extreme plastic deformation. The shear strength and ram tensile strength of the Al 5052/AZ31B welded plate were obtained 93 MPa and 146 MPa, respectively.

Bond behaviors and effects of brass interlayer on contact reaction brazing of 6061 and AZ31 alloys

Magnesium (Mg) and aluminum (Al) alloys were successfully contact reaction brazed (CRB) with the brass interlayer for the first time. By comparing joints brazed with and without the brass interlayer, we found that when no interlayer was used, the joints showed more precipitates and dispersoids, and inevitably Mg-Al intermetallic compounds (IMCs), with a shear strength of only 8 MPa. In contrast, the brass interlayer effectively inhibits the formation of Mg-Al IMCs, while ensuring that the brass is not completely consumed, metallurgical reactions occur with the base metal (BM) on both sides to form a well-bonded joint with a shear strength of 45 MPa, more than five times higher than the joint without brass interlayer.

Dissimilar laser lap welding of Mg and Al alloys using a CoCrFeNi medium-entropy alloy interlayer

Laser welding of Mg to Al dissimilar metals is of great significance in various industries, such as automobile, electrical, electronics, and energy systems, which promotes lightweight composite structure. However, Mg-Al intermetallic compounds (IMCs) have tremendous detrimental effects on the dissimilar metal joining of Mg to Al. In this work, dissimilar Mg/Al alloys joints with CoCrFeNi medium-entropy alloy (MEA) powders interlayer were achieved by the laser welding process, and the effect of different laser powers on the microstructure and mechanical properties of the joints was analyzed, reaching a maximum tensile shear strength of 100.12 MPa. The formation mechanism of the interface was investigated by experimental investigations and thermodynamic calculations. In addition, a numerical simulation of the laser welding process was carried out to reveal the temperature field of the molten pool and the flow change process. Based on the law of multi-component HEA phase formation, the interfacial metallurgical products were calculated and analyzed. The results of the energy dispersive spectroscopy show that the molten CoCrFeNi MEA powders reacted with Al to form Al-rich AlxCoCrFeNi phase, due to a more negative generation enthalpy compared to Mg-Al IMCs. With the increase of laser power, the Al-rich AlxCoCrFeNi phase mixed layer went through four states of agglomeration, continuity, interruption and dispersion, while the IMCs at the interface gradually increased and finally tend to be continuity. Due to the physical barrier of MEA and formation of Al-rich AlxCoCrFeNi phase, the formation of the Mg-Al IMCs phase was effectively suppressed, which improved the shear properties of the joints. The material- microstructure-property relations was established in this work, which facilitated the development of laser welding technology for Mg and Al alloys.

Effect of Annealing Temperature on Microstructure and Properties of Al/Mg Magnetic Pulse Welding Joints.

In this investigation, 1060Al/AZ31B welded joints were obtained by magnetic pulse welding technique. In order to test the microstructure and mechanical properties of the joints, the welded joints were annealed at different temperatures and then examined by optical microscopy (OM), scanning electron microscopy (SEM), energy spectrum analysis (EDS) and mechanical properties testing. The testing results of the welded joints annealed at different temperatures showed that the Al-Mg MPW welded joints were well bonded. The changing of the microstructure and mechanical properties of Al/Mg welded joints was not apparent under the temperature of 200 °C. However, Al12Mg17 intermetallic compound layer formed at 200 °C. Al12Mg17 and Al3Mg2 intermetallic compound layers formed at the temperature of 300 °C. The diffusion rate of Mg and Al elements is proportional to the annealing temperature and the intermetallic compounds layer is gradually formed. The microhardness near the interface decreased first and then increased on account of the brittleness of intermetallic compounds. In the tensile shear tests, the fracture mechanism of Al/Mg MPW welded joints were analyzed. When the temperature was lower than 200 °C the joints did not crack. At 200 °C and 250 °C, the joints fracture along the Al12Mg17-Al interface. The joint cracks along the interface of Al12Mg17-Al3Mg2 at the temperature of 300 °C.

Ultrafast ultrasonic-assisted transient liquid bonding Al/Mg in air

We used ultrasonic-assisted transient liquid bonding (UATLP) to join dissimilar Al/Mg alloys with pure Zn interlayer in the air to prevent the formation of AlMg intermetallic compounds (IMCs). The effects of bonding temperature, ultrasonic power, sonotrode pressure, and interlayer thickness on the microstructure and mechanical properties of the bonded joints were studied. Results showed that the addition of Zn interlayer could effectively depress the AlMg IMCs. The oxide layer on the Al substrate is incompletely removed at bonding temperature below 380 °C, the Mg side is bonded by eutectic phase, and the Al side is bonded by diffusion. The joint is characterized by MgZn eutectic (containing ternary IMCs) and IMCs of MgZn and MgZn2 layer. MgZn2 is the weak point of the joint under such a condition, and the joint has shear strength of approximately 20 MPa. The oxide layer on the Al substrate is completely removed when the temperature exceeds 380 °C, the large amount of Al that flows into the joint results in a Mg32(Al,Zn)49 layer adjacent to the Al substrate. The joint gains its maximum strength of 28.4 MPa when thin MgZn2 and discontinuous Mg32(Al,Zn)49 exist adjacent to the Al substrate. High ultrasonic power, large sonotrode pressure, and thin Zn interlayer could reduce the thickness of MgZn2.

Simultaneously enhanced the strength and ductility in Mg17Al12 intermetallic compound with Ce addition

In order to simultaneously improve the ductility and strength of Mg17Al12 intermetallic compound, a novel Mg17Al12-3Ce alloy was fabricated by addition appropriate Ce. The added Ce refines grains and reduces the proportion of wetted grain boundaries. Compared with the Mg17Al12 compound, the compressive properties of Mg17Al12-3Ce alloy are dramatically enhanced. The ultimate compressive strength increases by 86.5% (from 192.1 MPa to 358.2 MPa) and the compressive strain increases by 33.1% (from 1.75% to 2.33%). The enhanced strength and ductility of the compound are primarily attributed to the refined grains and reduced wetting grain boundaries. Additionally, the precipitation of the Al11Ce3 phase within the Mg17Al12-3Ce alloy also contributes to the improvement of the strength.

Diffusion of 65Zn in the Mg17Al12 intermetallic compound and in the Mg-33.4 wt.% Al eutectic

Abstract The coefficient of 65Zn heterodiffusion in the Mg17Al12 intermetallic compound (β-phase) and the eutectic alloy Mg-33.4 wt.% Al was measured in the temperature region 598 – 698 K using serial sectioning and residual activity methods. The diffusion coefficient of 65Zn in the intermetallic can be written as Δ I = 1.5 × 10– 2 m2 s –1 × exp( – 154.3 kJ mol –1/RT). At temperatures T ≥ 648 K, where the mean diffusion path is greater than the mean interlamellar distance in the eutectic, the effective diffusion coefficient Δ eff = 2.7 × 10– 2 m2 s –1 exp(–155.1 kJ mol– 1/ RT) was evaluated. At two lower temperatures, the diffusion coefficients 65Zn in interphase boundaries were estimated: Δ b (623 K) = 1.6 × 10 –12 m2 τ– 1 and Δ b (598 K) = 4.4 × 10– 13 m2 τ–1. The specific (Mg)/β interfacial energy γ = 140 mJ m– 2 was assessed from measurement of the time dependence of interlamellar distance during isothermal anneal.

Welding and Riveting Hybrid Bonding of 6061 Al and Carbon Fiber Reinforced Composites.

Welding and riveting hybrid bonding technology was applied to join 6061 aluminum alloy and carbon fiber reinforced plastics (CFRP). The laser-arc hybrid welding process and stepped rivets were used in the experiments to reduce the impact of the poor heat resistance of composites. The effect of hybrid welding arc current on the formation and mechanical properties of 6061 Al/CFRP joints was studied. Tensile shear load up to 4.65 kN was achieved by adjusting process parameters. The welding process and mode of the fracture were analyzed. The hybrid bonded joint obtained consisted of two parts: a welded joint of Al plate and Al rivet, and a bonded interface between Al plate and CFRP plate. The mechanical properties of the hybrid joint were mainly determined by the Al plate/Al rivet welded joint. The results of the study show that there are three interfacial bonding mechanisms between aluminum and CFRP. In addition to mechanical bonding between the Al plate and CFRP plate, there were also metallurgical bonding of Al-Mg intermetallic compounds with resin matrix and chemical reactions of aluminum with resin and carbon fibers at the interface, which could improve the mechanical properties of the joints.

Effect of electro-spark deposited ZA12 interlayer on the microstructure and mechanical property of A356/AZ91D by liquid-solid compound casting

In this paper, to fabricate high strength Al/Mg bimetallic composite without the formation of Al12Mg17 intermetallic compound at the interface, ZA12 deposited A356/AZ91D bimetal was achieved by liquid-solid compound casting. The combination between electro-spark technology and compound casting was realized. The process parameters of electro-spark deposition were optimized by considering the thickness, quality, and efficiency of the coating. The microstructure, phase composition and mechanical properties of A356/AZ91D bimetal without and with ZA12 coating were investigated. From AZ91D to A356, the main phases formed across the interface region are: Mg17(Al, Zn)12 + α-Mg in diffusion layer I, Al5Mg11Zn4 and Mg32(Al, Zn)49 in diffusion layer II, and Al3Mg2 and Mg2Si in diffusion layer III. The microhardness of the interface is obviously higher than that of the substrate on both sides. The average shear strength of ZA12 coated A356/AZ91D bimetal is 69.2 MPa. The interface microstructure evolution mechanism of ZA12 coated A356/AZ91D by liquid-solid compound casting was analyzed. The result is helpful for further development of high strength Al/Mg bimetallic composites.