The insufficient damping capabilities of aluminum alloy under low temperatures(<120℃)were addressed by developing high-damping laminated composites of NiTip/5052Al.This is achieved through the incorporation of var...The insufficient damping capabilities of aluminum alloy under low temperatures(<120℃)were addressed by developing high-damping laminated composites of NiTip/5052Al.This is achieved through the incorporation of varied pre-aging states of NiTi particles into the 5052Al matrix using a rolling composite technique.The aim is to enhance the application scope of aluminum alloy for vibration and noise reduction.The results demonstrated a distinct and integrated interface between the particle layer and the 5052Al alloy,with numerous interparticle interfaces within the particle layer.Increasing the aging temperature of the NiTi particles from 450 to 550℃ shifted the phase transition peaks of the composites to lower temperatures.The damping capacity of the laminated NiTip/5052Al composites notably surpasses that of the 5052Al alloy.At 28 and 66℃,the phase transformation damping peaks of the pre-aged NiTi particle layer reinforced 5052Al matrix composites are 1.93 and 2 times those of the 5052Al alloy at the corresponding temperatures,respectively.The collaborative impact of interparticle interface damping mechanism and the phase transformation damping mechanism of NiTi-reinforced particles significantly amplify the low-temperature damping performance of the laminated NiTip/5052Al composites.展开更多
The influence of geometric configuration on the friction characteristics during incremental sheet forming of AA5052 was analyzed by integrating surface morphology and its characteristic parameters,along with plastic s...The influence of geometric configuration on the friction characteristics during incremental sheet forming of AA5052 was analyzed by integrating surface morphology and its characteristic parameters,along with plastic strain,contact pressure,and area.The interface promotes lubrication and support when wall angles were≤40°,a 0.5 mm-thin sheet was used,and a 10 mm-large tool radius was employed.This mainly results in micro-plowing and plastic extrusion flow,leading to lower friction coefficient.However,when wall angles exceed 40°,significant plastic strain roughening occurs,leading to inadequate lubrication on the newly formed surface.Increased sheet thickness and decreased tool radius elevate contact pressure.These actions trigger micro-cutting and adhesion,potentially leading to localized scuffing and dimple tears,and higher friction coefficient.The friction mechanisms remain unaffected by the part’s plane curve features.As the forming process progresses,abrasive wear intensifies,and surface morphology evolves unfavorably for lubrication and friction reduction.展开更多
The microstructures and mechanical properties of homogenized-rolled AA5052 aluminum alloys with different rolling reductions and following annealing treatments were investigated by optical microscope, scanning electro...The microstructures and mechanical properties of homogenized-rolled AA5052 aluminum alloys with different rolling reductions and following annealing treatments were investigated by optical microscope, scanning electron microscope, X-ray diffractometer, micro-hardness and tensile tests. The results show that with increasing rolling reduction, the equiaxed grains are elongated along the rolling direction obviously, and accumulation of rolling reduction increases the work hardening effect, which results in the enhanced strength and degraded plasticity. When rolling reduction is 87%, the ultimate tensile strength reaches 325 MPa but elongation is only 2.5%. There are much more secondary phase precipitates after annealing treatment. With an increase of annealing temperature, the amount of precipitates increases and work hardening diminishes continuously. The elongation is improved to ~23% but the tensile strength is decreased to 212 MPa after annealing at 300 °C for 4 h, which are comparable to those of as-homogenized alloy.展开更多
基金National Natural Science Foundation of China (No. 52061011)Guangxi Natural Science Foundation,China (No. 2022GXNSFAA035574)Innovation Project of Guangxi Graduate Education,China (No. YCSW2023361)。
文摘The insufficient damping capabilities of aluminum alloy under low temperatures(<120℃)were addressed by developing high-damping laminated composites of NiTip/5052Al.This is achieved through the incorporation of varied pre-aging states of NiTi particles into the 5052Al matrix using a rolling composite technique.The aim is to enhance the application scope of aluminum alloy for vibration and noise reduction.The results demonstrated a distinct and integrated interface between the particle layer and the 5052Al alloy,with numerous interparticle interfaces within the particle layer.Increasing the aging temperature of the NiTi particles from 450 to 550℃ shifted the phase transition peaks of the composites to lower temperatures.The damping capacity of the laminated NiTip/5052Al composites notably surpasses that of the 5052Al alloy.At 28 and 66℃,the phase transformation damping peaks of the pre-aged NiTi particle layer reinforced 5052Al matrix composites are 1.93 and 2 times those of the 5052Al alloy at the corresponding temperatures,respectively.The collaborative impact of interparticle interface damping mechanism and the phase transformation damping mechanism of NiTi-reinforced particles significantly amplify the low-temperature damping performance of the laminated NiTip/5052Al composites.
基金the support of the Key Research and Development Program of Shaanxi Province,China(No.2021GXLH-Z-049)。
文摘The influence of geometric configuration on the friction characteristics during incremental sheet forming of AA5052 was analyzed by integrating surface morphology and its characteristic parameters,along with plastic strain,contact pressure,and area.The interface promotes lubrication and support when wall angles were≤40°,a 0.5 mm-thin sheet was used,and a 10 mm-large tool radius was employed.This mainly results in micro-plowing and plastic extrusion flow,leading to lower friction coefficient.However,when wall angles exceed 40°,significant plastic strain roughening occurs,leading to inadequate lubrication on the newly formed surface.Increased sheet thickness and decreased tool radius elevate contact pressure.These actions trigger micro-cutting and adhesion,potentially leading to localized scuffing and dimple tears,and higher friction coefficient.The friction mechanisms remain unaffected by the part’s plane curve features.As the forming process progresses,abrasive wear intensifies,and surface morphology evolves unfavorably for lubrication and friction reduction.
基金Project(2011DFR50950)supported by the International Science and Technology Cooperation Program of ChinaProject(2012BAF09B04)supported by the National Key Technology Research and Development Program of ChinaProject(CSTC2013JCYJC60001)supported by Chongqing Science and Technology Commission,China
文摘The microstructures and mechanical properties of homogenized-rolled AA5052 aluminum alloys with different rolling reductions and following annealing treatments were investigated by optical microscope, scanning electron microscope, X-ray diffractometer, micro-hardness and tensile tests. The results show that with increasing rolling reduction, the equiaxed grains are elongated along the rolling direction obviously, and accumulation of rolling reduction increases the work hardening effect, which results in the enhanced strength and degraded plasticity. When rolling reduction is 87%, the ultimate tensile strength reaches 325 MPa but elongation is only 2.5%. There are much more secondary phase precipitates after annealing treatment. With an increase of annealing temperature, the amount of precipitates increases and work hardening diminishes continuously. The elongation is improved to ~23% but the tensile strength is decreased to 212 MPa after annealing at 300 °C for 4 h, which are comparable to those of as-homogenized alloy.
