Effect Of Ultrasonic Vibration On Microstructure And Properties Of Aluminum Bronze Alloy Produced By Wire Arc Additive Manufacturing

Aluminum bronze alloy has good strength,corrosion resistance and wear resistance,and has wide application prospects in structures such as marine installations and seawater treatment installations.For large monolithic structural parts with complex shapes,traditional processing methods mainly use casting,forging,welding,bolting,and mechanical processing,which results in low material utilization,high manufacturing costs,and long production cycles.Additive manufacturing technology is one of the advanced manufacturing technologies that have developed rapidly in recent years.Due to the advantages of high efficiency,low cost,and high density,wire arc additive manufacturing(WAAM)technology has become a potential feasibility for the manufacture of large components.Program.Structures manufactured by arc additive often cause anisotropy of mechanical properties due to the directional solidified columnar crystal structure.During the metal solidification process,proper ultrasonic vibration(Ultrasonic vibration,UV)can be applied properly to break the primary crystal nucleus.,Improve the nucleation rate,inhibit the growth of crystal grains,so as to obtain uniformly distributed and uniformly sized grains.Therefore,in the process of arc addition,ultrasonic vibration is introduced in order to eliminate or suppress the columnar dendrites easily formed in the addition process,refine the grains,and optimize the anisotropy of mechanical properties.This paper studies the thin-walled aluminum bronze(Cu-8Al-2Fe-2Ni-2Mn,wt.%)Samples prepared by WAAM at different interlayer temperatures(continuous additive,400?,100?)and with or without ultrasonic vibration.Effects of microstructure characteristics(including macrostructure,microstructure,element distribution and phase composition),mechanical properties(including nano-hardness and tensile strength)and corrosion properties.The following conclusions can be drawn:1.The microstructure in the Cu-8Al-2Fe-2Ni-2Mn alloy manufactured by arc additive without ultrasonic vibration is mainly manifested in three areas:the first three layers of microstructure are the areas where the substrate dendrites are transformed into columnar crystal;The stable area of the third layer to the last layer,its microstructure is mainly uniform columnar crystals growing perpendicular to the direction of the substrate;the top area has formed about 350-400?m thick turning dendrites.At different interlayer cooling temperatures,directional growth of columnar dendrites will be formed,and the number of secondary dendrites will decrease as the interlayer cooling temperature decreases.Continuous addition,interlayer cooling temperature 400?and interlayer cooling temperature 100 The width of columnar dendrites at?is 33.7±3.2?m,28.5±4.2?m,and 21.6±3.6?m.2.After the introduction of ultrasonic vibration,the width of columnar crystals in the samples with continuous additive and interlayer cooling temperature of 400°C decreased to 31.2±3.1?m and 26.8±3.1?m,respectively,without obvious secondary dendrites.In the sample with interlayer cooling temperature of 100?,irregularly distributed cell crystals were obtained,the formation of columnar dendrites was suppressed,and its size was about 18.6±2.6?m.In addition,ultrasonic vibration improves the spread-ability of the molten pool.In the sample with an interlayer cooling temperature of 100°C,the effective use area of the additive area reaches 84.8%.3.The phase composition of Cu-8Al-2Fe-2Ni-2Mn alloy produced by arc additive manufacturing is clarified,that is,the spherical?_II phase based on Fe₃Al and the layered?_III phase based on Ni Al,and the?_IV phase(iron-rich)are included between dendrite Uneven nucleation in the?-Cu matrix,and twins and dislocations were observed in the alloy after the introduction of ultrasonic vibration.4.The microhardness of dendrite and?-Cu matrix under different parameters.Compared with?-Cu matrix,the nano-hardness and modulus of the two are different.The nano-hardness and modulus of dendrite show more High value.By reducing the interlayer temperature and introducing ultrasonic vibration,the nano-hardness and modulus of the?-Cu matrix can be increased.Under the condition of ultrasonic vibration+interlayer cooling temperature of 100°C,the nano-hardness and modulus of the alloy in different areas are more uniform,with the nano-hardness distribution ranging from 2.11 to 2.28GPa and the modulus distribution ranging from 122.4 to 129.4 GPa.5.The effect of interlayer cooling temperature and ultrasonic vibration on the tensile properties.The tensile properties showed anisotropy in the samples of interlayer cooling temperature 100?,ultrasonic vibration+interlayer cooling temperature 400?,that is,the horizontal direction The tensile strength is better than the vertical direction,and the tensile strength in the horizontal direction will decrease with the increase of the deposition height,and the elongation will show the opposite result.The anisotropy of tensile properties at ultrasonic vibration+interlayer cooling temperature of 100?was effectively controlled,and the average values of tensile strength,yield strength and elongation were 517.0±0.89MPa,226.2±0.95MPa and 41.01±0.29%,respectively.The tensile fractures all show the characteristics of plastic fracture,and as the cooling temperature of the interlayer decreases,the tensile fractures develop from"slip separation"to the direction of"dimple".6.Corrosion performance of Cu-8Al-2Fe-2Ni-2Mn alloy manufactured by arc additive under different parameters.The self-corrosion current density Icorr decreases in turn as the interlayer cooling temperature decreases;meanwhile,the Cu-8Al-2Fe-2Ni-2Mn alloy with ultrasonic vibration introduced at the same interlayer cooling temperature shows a lower self-corrosion current density Icorr The results show that reducing the interlayer temperature and introducing ultrasonic vibration are beneficial to improve the corrosion resistance of the alloy.At the same time,under the condition of ultrasonic vibration+interlayer cooling temperature of 100?,the alloy has a lower self-corrosion current density Icorr,which is only 18.2%compared with the continuous additive sample,and shows the best corrosion resistance.The self-corrosion current density Icorr of the continuous additive sample reached 1.6132×10^-5A/cm2,showing the worst corrosion resistance.The corrosion rate of Cu-8Al-2Fe-2Ni-2Mn alloy with ultrasonic vibration+interlayer cooling temperature of 100?in the immersion corrosion test is accelerated as the temperature increases.The corrosion rates of 20?,40?,60?are 0.0405mm/a,0.0501mm/a,0.0803mm/a,all show good corrosion resistance.The formation of Cu₂O and Al₂O₃on the corroded surface has a certain protective effect on the aluminum bronze matrix.The main corrosion product of the alloy is basic copper chloride Cu₂(OH)₃Cl,which shows a biconical crystals.