| Aluminum bronze alloys has been widly used in some area such as aerospaceand marine engineering because it possesses some super properties, for exampleexcellent mechanical performance and physical properties. With the rapiddevelopment of modern science and technology industries, traditional trademark’saluminum bronze don’t accord with usefulness request in the certain situation. It isnecessary to develope new types of high aluminum bronze alloys. High aluminumbronze alloy has poor processability because of many brittle phases are exist,meanwhile it is less study on hot deformation process of aluminum bronze alloy. Inthis study, experiments were carried out to optimize the thermal deformationparameters and heat treatment process parameters, then discuss the relationshipbetween annealing process and plastic deformation capacity of the alloy, and in orderto high-aluminum bronze alloy has optimum properties.The alloy used in the present study was made by ingot metallurgy. Usingobserve metallurgical structure, tensile test at room temperature, hardnessmeasurement, XRD and SEM.The microstructure and mechanical property of thealloy under different processing and heat treatment was researched.The compreh--ensive research results are as follows.(1) The as-cast aluminum bronze alloy microstructure is mainly composed of α、β′、γ2、κ phases. The content of α phase decreased and the content of β′phase、eutectoid and hardness value increased with the increasing of the contents of Al; whilethe contents of Al increase to12.2%,it′s hardness、tensile strength and elongation ofthe alloy were290HB、797MPa and11.6%respectively;During hot deformation, themicrostructure of the alloy is composed of mass α phase, eutectoid and κ phase whichis distributed along the deformation direction. The content of α phase decreased andeutectoid and hardness value increased with the increasing of the contents of Al.Afterhigh temperature deformation heat treatment, the microstructure of the alloy iscomposed of strip α phase which is distributed along deformation direction, β′phase,k phase and a small amount of granular eutectoid. The higher hardness was obtainedafter high temperature deformation heat treatment.(2) With an increase of the solution temperature, the hardness of the alloyincreased first and then decline after reaching a peak hardness. The hardness of thealloy increased with the increasing of the content of Al. The higher hardness andstrength of the forged alloy was obtained after solution and quenching as the results ofβ-β′martensite transformation and solution strengthening. The optimal solutionregime of thermal deformation QAl10.7、QAl10.9、QAl11.2、QAl12.2are925℃、925℃、950℃、950℃, when the solution time is1h.(3) The mechanical properties of the high temperature thermal and hot roll solidsolution can be further improved after aging treatment. The hardness shows a trend ofincreasing at first and then decreasing with aging temperature when aging timeremains constant. With the increase of the content of aging time, the hardnessincreases at first, then decreases when aging temperature remains constant. The peak hardness increased gradually with Al content increasing. The optimal aging process ofQAl10.7、QAl10.9、QAl11.2in hot-rolled solid solution is450℃×2h,and450℃×3h isthe optimal aging process for QAl12.2alloy.the thermal mechanical treatmentQAl10.9alloy prepared ageing on450℃for2hours has better comprehensivemechanical properties, hardness, strength and elongation of the alloy were40.2HRC、975MPa、5.5%,respectively.It can be concluded that the best thermal deformationprocess is high temperature thermal mechanical treatment.(4)After hot rolling, annealing of air cooling, the hard and brittle of eutectoidwas uniformly distributed among the soft a phase, less k phase dispersed on themicrostructure.More fine granular κ phase was uniformly distributed among the soft aphase after furnace cooling. The hardness of alloy after annealing are lower than thoseof hot-rolled, and the hardness of alloy under furnace cooling is lower than thoseunder air cooling.The optimum annealing process of hot-rolled QAl10.7, QAl10.9,QAl11.2alloy is750×2h, and optimal annealing process for QAl12.2is600℃×2h.(5) After hot rolling and annealing, the plastic deformation resistance of thealuminum bronze alloy decreased gradually with an increase of Al content. The plasticdeformation capacity of the alloy under furnace cooling was better than the alloywhich is under air cooling. As for high aluminum bronze alloy after cold plasticdeformation and annealing at450℃×2h, furnace cooling and low temperatureannealing has simultaneously a comparable impact which causes hardness to declined.After hot rolling, annealing at600℃×2h,air cooling, cold rolling and annealing at450℃×2h, the hardness, tensile strength, andelongation of the QAl12.2alloy reaches324.5HB、935MPa、1.5%. |
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