Study On The Fabrication And Properties Of Magnesium Aluminum Titanium Laminated Sheet

In this article,magnesium aluminum titanium sandwich sheet was produced by hot roll-bonding, magnesium aluminum titanium laminated sheet of different stacking sequence and thickness ratio was produced to select the optimal magnesium aluminum titanium laminated frame, then the design of magnesium aluminum titanium laminated sheet rolling temperature is 350 oC, 400 oC, 450 oC, rolling reduction is 20%, 30%, 40%, 50%, the annealing temperature is 200 oC, 300 oC, 400 oC. Analysis techniques like optical microscope(OM), micro-hardness test, tensile machine, scanning electron microscope(SEM), X-ray diffraction(XRD) and so on were used to study effect of stacking sequence, thickness ratio, rolling temperature and rolling reduction, annealing temperature on the microstructure and properties of laminated sheet.The results show that Stacking sequence of laminated sheet is Al/Mg/Ti, Mg/Al/Ti, Al/Ti/Mg. The comparison of their performance know that the stacking sequence is Al/Mg/Ti, rolling process is very difficult, and even the emergence of macroscopic fracture failure. Performance of Mg/Al/Ti laminated sheet is better than other stacking sequence.In the condition of different thickness ratio, we can find that when the initial layer sheet in the total sheet in the proportion is higher, and its contribution to the total deformation is higher. Ti layer in the total deformation accounted for a relatively small, accounted for only a small fraction of less than 10%, and Al, Mg accounted for about 90% of total deformation, and the mechanical properties of Mg/Al/Ti composite plate matched theoretical intensity formula of composite plate. Therefore, thickness ratio of Mg layer Al layer Ti layer is 2:2:1, the Ti layer of the relative proportion of the other 2 stacking sequence of a higher proportion, therefore the mechanical properties are the best.In the different rolling temperature, observation of the optical image, we can find Mg/Al interface and Al/Ti interface is flat, at the same time we can know that with a rise of temperature plate interface is more flat, the deformation is more collaborative, the interface is more excellent. Under 350 oC and 400 oC of rolling temperature, Mg layer show hot rolled microstructure significantly, while rolling in 450 oC, Mg layer was obtained with dynamic recrystallization, so the comprehensive comparison of rolling in 450 oC, the mechanical properties and microstructure of the laminated sheet are excellent.In the rolling temperature under 450 oC, with different deformation reduction to fabricate Mg/Al/Ti three layer composite plate, when the reduction is 20%, Al/Ti bonding interface is not bonded,Under reduction of 30%, Mg/Al interface and Al /Ti interface is flat, while, as the amount of reduction is greater than 40%, the middle layer of aluminum appeared localized necking phenomenon, If temperature of 450 oC and reduction reached to 40%, the tensile mechanical properties of the sheet is best, the tensile strength is 521 MPa, elongation is 15.9%, the Mg/Al and Al/Ti interface bonding strength are 55.2MPa, 68.5MPa respectively.With the increase of annealing temperature, the strength of the sheet decreased slightly, while the elongation at 200 oC to 300 oC gradually increased, decreased from 300 oC to 400 oC, using the XRD techniques to analysis, we find that the annealing temperature is 200 oC, the Mg/Al interface does not produce intermetallic compounds, the annealing temperature was 300 oC, Mg/Al interface will appear Al3Mg2 of the brittle intermetallic compound, with a rise of temperature at 400 oC, the interface will appear a large number of brittle intermetallic compounds,such as All3Mg2, Al12Mg17, Mg2 Si. using EDS analysis method, we find that the annealing temperature is 400 oC, the thickness of the interfacial layer is increased to 59.8μm. After annealing at 400 oC and 1h, the fracture of Al and Ti layer have a large number of dimples, the fracture mode was ductile fracture. The fracture morphology of Mg layer is composed of cleavage like river,it is brittle fracture. As can be seen from the chart,between Al and Mg find the mixed fracture phenomenon,The fracture morphology of the Mg/Al interface included both characteristics of ductile fracture and brittle fracture characteristics. Emergence of dimples in the Al layer, but there was a brittle fracture near the interface, the Mg layer appeared obvious cleavage fracture characteristics. Based on the above analysis, the magnesium aluminum titanium laminated sheet should choose annealing process at low temperature(200 oC).