采用等离子电弧沉积法分别在GT35和40CrNiMo钢上沉积厚约为0.5 mm 的TiN膜。为了检测成膜质量,在较宽的载荷范围内分别使用显微硬度、纳米压痕和纳米划痕技术表征钢基材和TiN/基材的微力学和摩擦性能。同TiN/40CrNiMo相比,TiN/GT35的硬...采用等离子电弧沉积法分别在GT35和40CrNiMo钢上沉积厚约为0.5 mm 的TiN膜。为了检测成膜质量,在较宽的载荷范围内分别使用显微硬度、纳米压痕和纳米划痕技术表征钢基材和TiN/基材的微力学和摩擦性能。同TiN/40CrNiMo相比,TiN/GT35的硬度高和固体润滑效果显著,GT35是较为理想的基体材料。对这种亚微米厚的膜,纳米压痕技术和纳米划痕技术能提供丰富的近表面的弹塑性变形、断裂和摩擦等的信息。展开更多
The dynamic process of the evaporation and the desiccation of sessile saline colloidal droplets,and their final deposition are investigated.During the evaporation,the movement of the colloidal particles shows a strong...The dynamic process of the evaporation and the desiccation of sessile saline colloidal droplets,and their final deposition are investigated.During the evaporation,the movement of the colloidal particles shows a strong dependence on the salt concentration and the droplet shape.The final deposition pattern indicates a weakened coffee-ring effect in this mixed droplet system.The microscopic observation reveals that as evaporation proceeds,the particle motion trail is affected by the salt concentration of the droplet boundary.The Marangoni flow,which is induced by surface tension gradient originating from the local evaporative peripheral salt enrichment,suppresses the compensation flow towards the contact line of the droplet.The inhomogeneous density and concentration field induced by evaporation or crystallization can be the major reason for various micro-flows.At last stage,the distribution and crystallization of Na Cl are affected by the colloidal particles during the drying of the residual liquid film.展开更多
We report an enhanced rejuvenation in hot-drawn micrometer metallic glassy wires(MG wires)with the size reduction.Compared to metallic glasses(MGs)in bulk form,the modulus and hardness for the micro-scale MG wires,tes...We report an enhanced rejuvenation in hot-drawn micrometer metallic glassy wires(MG wires)with the size reduction.Compared to metallic glasses(MGs)in bulk form,the modulus and hardness for the micro-scale MG wires,tested by nanoindentation methods,are much lower and decrease with the decreasing size,with a maximum decrease of〜26%in modulus and^17%in hardness.This pronounced rejuvenation is evidenced by the larger sub-Tg relaxation enthalpy of the MG wires.The pronounced rejuvenation is physically related to the higher energy state induced by a combined effect of severely thermomechanical shearing and freezing the shear How into a constrained small-volume region.Our results reveal that the internal states and properties of MGs can be dramatically changed by a proper modulation of temperature,flow stress and size.展开更多
文摘采用等离子电弧沉积法分别在GT35和40CrNiMo钢上沉积厚约为0.5 mm 的TiN膜。为了检测成膜质量,在较宽的载荷范围内分别使用显微硬度、纳米压痕和纳米划痕技术表征钢基材和TiN/基材的微力学和摩擦性能。同TiN/40CrNiMo相比,TiN/GT35的硬度高和固体润滑效果显著,GT35是较为理想的基体材料。对这种亚微米厚的膜,纳米压痕技术和纳米划痕技术能提供丰富的近表面的弹塑性变形、断裂和摩擦等的信息。
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11472275 and U1738118)the Chinese Academy of Sciences Key Technology Talent Programthe Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB22040301)
文摘The dynamic process of the evaporation and the desiccation of sessile saline colloidal droplets,and their final deposition are investigated.During the evaporation,the movement of the colloidal particles shows a strong dependence on the salt concentration and the droplet shape.The final deposition pattern indicates a weakened coffee-ring effect in this mixed droplet system.The microscopic observation reveals that as evaporation proceeds,the particle motion trail is affected by the salt concentration of the droplet boundary.The Marangoni flow,which is induced by surface tension gradient originating from the local evaporative peripheral salt enrichment,suppresses the compensation flow towards the contact line of the droplet.The inhomogeneous density and concentration field induced by evaporation or crystallization can be the major reason for various micro-flows.At last stage,the distribution and crystallization of Na Cl are affected by the colloidal particles during the drying of the residual liquid film.
基金the National Key Research and Development Program of China under Grant Nos.2018YFA0703603,2017YFB0903902,and 2016YFB0300501the National Natural Science Foundation of China under Grant Nos.51822107,11790291,51671121,and 51761135125+2 种基金the National Natural Science Foundation of Guangdong Province under Grant No.2019B030302010the Key Research Program of Frontier Sciences(QYZDY-SSW-JSC017)the Strategic Priority Research Program of Chinese Academy of Sciences under Grant No.XDB30000000.
文摘We report an enhanced rejuvenation in hot-drawn micrometer metallic glassy wires(MG wires)with the size reduction.Compared to metallic glasses(MGs)in bulk form,the modulus and hardness for the micro-scale MG wires,tested by nanoindentation methods,are much lower and decrease with the decreasing size,with a maximum decrease of〜26%in modulus and^17%in hardness.This pronounced rejuvenation is evidenced by the larger sub-Tg relaxation enthalpy of the MG wires.The pronounced rejuvenation is physically related to the higher energy state induced by a combined effect of severely thermomechanical shearing and freezing the shear How into a constrained small-volume region.Our results reveal that the internal states and properties of MGs can be dramatically changed by a proper modulation of temperature,flow stress and size.
