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
本文采用了粉末冶金法制备了SiC含量为30%体积分数SiCp/Al复合材料,并在180℃条件下进行固溶时效处理,研究了在300℃和400℃温度下氧化处理后SiCp/Al复合材料的微观组织。以GCr15小球为摩擦对偶对高温氧化后SiCp/Al复合材料进行往复式...本文采用了粉末冶金法制备了SiC含量为30%体积分数SiCp/Al复合材料,并在180℃条件下进行固溶时效处理,研究了在300℃和400℃温度下氧化处理后SiCp/Al复合材料的微观组织。以GCr15小球为摩擦对偶对高温氧化后SiCp/Al复合材料进行往复式摩擦磨损实验,研究不同氧化温度对摩擦磨损行为的影响规律。结果表明:经过25 h高温氧化之后,SiCp/Al复合材料的样品硬度总体都是降低的。300℃-25 h试样硬度下降的原因Al2CuMg和Al2Cu在晶界析出且尺寸更加细小,破坏了晶界的连续性,引发晶界弱化。基体中Mg元素的固溶减少,削弱了固溶强化,晶界弱化是300℃-25 h试样材料损伤的主导原因。而400℃-25 h试样硬度下降是因为界面处脆性的MgAl2O4相导致界面结合强度降低,热应力与MgAl2O4脆性协同作用,是造成材料损伤显著增加的主要原因;SiCp/Al复合材料经过300℃氧化处理后其磨损量增加,摩擦系数较高。而400℃-25 h试样的磨损量接近于烧结态,摩擦系数较低。磨损量的差异是因为不同的硬度以及界面强度造成的,摩擦系数的差异取决于表面氧化膜的组成不同;SiCp/Al复合材料烧结态和400℃-25 h试样的磨损机制主要为磨粒磨损,300℃-25 h试样其磨损机制由磨粒磨损为主转变为粘着磨损为主、磨粒磨损为辅。In this paper, SiCp/Al composites with 30% volume fraction of SiC were prepared by powder metallurgy method, and the microstructure of SiCp/Al composites after oxidation treatment at 300˚C and 400˚C was studied by solution aging treatment at 180˚C. Reciprocating friction and wear experiments were carried out on SiCp/Al composites after high temperature oxidation using GCr15 small balls as friction pairs, and the influence of different oxidation temperatures on friction and wear behavior was studied. The results show that after 25 h of high-temperature oxidation, the sample hardness of SiCp/Al composites decreases in general. The reason for the decrease of the hardness of the sample at 300˚C-25 h is that Al2CuMg and Al2Cu are precipitated at the grain boundary and the size is smaller, which destroys the continuity of the grain boundary and causes the weakening of the grain boundary. The reduction of the solid solution of Mg in the matrix weakened the solution strengthening, and the weakening of grain boundaries was the main reason for the material damage of the sample at 300˚C-25 h. However, the decrease in hardness of the 400˚C-25 h specimen is due to the decrease of the interfacial bonding strength caused by the brittle MgAl2O4 spinel phase at the interface, and the synergistic effect of thermal stress and MgAl2O4 brittleness is the main reason for the significant increase of material damage. After 300˚C oxidation treatment, the wear of SiCp/Al composites increases, and the friction coefficient is high. However, the wear amount of the 400˚C-25 h specimen is close to that of the sintered state, and the friction coefficient is low. The difference in the amount of wear is caused by different hardness and interfacial strength, and the difference in friction coefficient depends on the composition of the surface oxide film. The wear mechanism of SiCp/Al composites in the sintered state and 400˚C-25 h samples is mainly abrasive wear, and the wear mechanism of 300˚C-25 h samples is mainly abrasive wear to adhesion wear and abrasive wear is supplemented.展开更多
SiC-reinforced aluminum matrix(SiCp/Al)composite is widely utilized in the aerospace,automotive,and electronics industries due to the combination of ceramic hardness and metal toughness.However,the significant dispari...SiC-reinforced aluminum matrix(SiCp/Al)composite is widely utilized in the aerospace,automotive,and electronics industries due to the combination of ceramic hardness and metal toughness.However,the significant disparity in properties between SiC particles and the aluminum matrix results in severe tool wear and diminished surface quality during conventional machining.This study proposes an environmentally friendly and clean dry electrical discharge assisted grinding process as an efficient and low-damage machining method for SiCp/Al.An experimental platform was set up to study the impact of grinding and discharge process parameters on surface quality.The study compared the chip formation mechanism and surface quality between dry electrical discharge assisted grinding and conventional grinding,revealing relationships between surface roughness,grinding force,grinding temperature,and related parameters.The results indicate that the proposed grinding method leads to smaller chip sizes,lower grinding forces and temperatures,and an average reduction of 19.2%in surface roughness compared to conventional grinding.The axial,tangential,and normal grinding forces were reduced by roughly 10.5%,37.8%,and 23.0%,respectively.The optimized process parameters were determined to be N=2500 r/min,vf=30 mm/min,a=10μm,E=15 V,f=5000 Hz,dc=80%,resulting in a surface roughness of 0.161μm.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.
文摘本文采用了粉末冶金法制备了SiC含量为30%体积分数SiCp/Al复合材料,并在180℃条件下进行固溶时效处理,研究了在300℃和400℃温度下氧化处理后SiCp/Al复合材料的微观组织。以GCr15小球为摩擦对偶对高温氧化后SiCp/Al复合材料进行往复式摩擦磨损实验,研究不同氧化温度对摩擦磨损行为的影响规律。结果表明:经过25 h高温氧化之后,SiCp/Al复合材料的样品硬度总体都是降低的。300℃-25 h试样硬度下降的原因Al2CuMg和Al2Cu在晶界析出且尺寸更加细小,破坏了晶界的连续性,引发晶界弱化。基体中Mg元素的固溶减少,削弱了固溶强化,晶界弱化是300℃-25 h试样材料损伤的主导原因。而400℃-25 h试样硬度下降是因为界面处脆性的MgAl2O4相导致界面结合强度降低,热应力与MgAl2O4脆性协同作用,是造成材料损伤显著增加的主要原因;SiCp/Al复合材料经过300℃氧化处理后其磨损量增加,摩擦系数较高。而400℃-25 h试样的磨损量接近于烧结态,摩擦系数较低。磨损量的差异是因为不同的硬度以及界面强度造成的,摩擦系数的差异取决于表面氧化膜的组成不同;SiCp/Al复合材料烧结态和400℃-25 h试样的磨损机制主要为磨粒磨损,300℃-25 h试样其磨损机制由磨粒磨损为主转变为粘着磨损为主、磨粒磨损为辅。In this paper, SiCp/Al composites with 30% volume fraction of SiC were prepared by powder metallurgy method, and the microstructure of SiCp/Al composites after oxidation treatment at 300˚C and 400˚C was studied by solution aging treatment at 180˚C. Reciprocating friction and wear experiments were carried out on SiCp/Al composites after high temperature oxidation using GCr15 small balls as friction pairs, and the influence of different oxidation temperatures on friction and wear behavior was studied. The results show that after 25 h of high-temperature oxidation, the sample hardness of SiCp/Al composites decreases in general. The reason for the decrease of the hardness of the sample at 300˚C-25 h is that Al2CuMg and Al2Cu are precipitated at the grain boundary and the size is smaller, which destroys the continuity of the grain boundary and causes the weakening of the grain boundary. The reduction of the solid solution of Mg in the matrix weakened the solution strengthening, and the weakening of grain boundaries was the main reason for the material damage of the sample at 300˚C-25 h. However, the decrease in hardness of the 400˚C-25 h specimen is due to the decrease of the interfacial bonding strength caused by the brittle MgAl2O4 spinel phase at the interface, and the synergistic effect of thermal stress and MgAl2O4 brittleness is the main reason for the significant increase of material damage. After 300˚C oxidation treatment, the wear of SiCp/Al composites increases, and the friction coefficient is high. However, the wear amount of the 400˚C-25 h specimen is close to that of the sintered state, and the friction coefficient is low. The difference in the amount of wear is caused by different hardness and interfacial strength, and the difference in friction coefficient depends on the composition of the surface oxide film. The wear mechanism of SiCp/Al composites in the sintered state and 400˚C-25 h samples is mainly abrasive wear, and the wear mechanism of 300˚C-25 h samples is mainly abrasive wear to adhesion wear and abrasive wear is supplemented.
基金Supported by National Natural Science Foundation of China(Grant Nos.52475480,51805334)Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2023A1515030249,2023A1515110059)Shenzhen Science and Technology Program(Grant No.GJHZ20220913144212023).
文摘SiC-reinforced aluminum matrix(SiCp/Al)composite is widely utilized in the aerospace,automotive,and electronics industries due to the combination of ceramic hardness and metal toughness.However,the significant disparity in properties between SiC particles and the aluminum matrix results in severe tool wear and diminished surface quality during conventional machining.This study proposes an environmentally friendly and clean dry electrical discharge assisted grinding process as an efficient and low-damage machining method for SiCp/Al.An experimental platform was set up to study the impact of grinding and discharge process parameters on surface quality.The study compared the chip formation mechanism and surface quality between dry electrical discharge assisted grinding and conventional grinding,revealing relationships between surface roughness,grinding force,grinding temperature,and related parameters.The results indicate that the proposed grinding method leads to smaller chip sizes,lower grinding forces and temperatures,and an average reduction of 19.2%in surface roughness compared to conventional grinding.The axial,tangential,and normal grinding forces were reduced by roughly 10.5%,37.8%,and 23.0%,respectively.The optimized process parameters were determined to be N=2500 r/min,vf=30 mm/min,a=10μm,E=15 V,f=5000 Hz,dc=80%,resulting in a surface roughness of 0.161μm.
