Ultrasonic Assisted Sintering Using Heat Converted from Mechanical Energy
Ultrasonic Assisted Sintering Using Heat Converted from Mechanical Energy
复制标题
利用机械能转化的热量进行超声波辅助烧结
DOI：
10.3390/met10070971
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发表时间：
2020-07-01
期刊：
影响因子：
2.9
通讯作者：
Yu, Chunyan
中科院分区：
文献类型：
--
作者：
Liu, Zhiyuan;Ge, Yang;Yu, Chunyan
提出了一种新的烧结方法，即超声辅助烧结（UAS），利用高频运动转化的机械热来实现烧结。直径为5 mm、厚度接近2 mm的纯铝试样在2秒内成功烧结。基于热力学分析，定量解释了其加热机制，即高频颗粒间摩擦和超声挤压驱动的塑性变形。因此，温度以约300 K/s的速度快速上升，并且在UAS期间最高温度达到铝熔点的0.9倍。烧结试样中位错密度较高，在位错和起伏应力场的共同作用下，烧结体扩散系数提高了几个数量级，可在几秒钟内实现快速致密化。此外，烧结铝具有纳米硬度（类似于1.13 GPa），这可以归因于UAS过程中形成的分级结构。
A new sintering method, namely ultrasonic assisted sintering (UAS), has been proposed using mechanical heat converted from high frequency motion between particles. Pure aluminum specimens with diameter of 5 mm and thickness of similar to 2 mm have been successfully sintered in two seconds. Based on the thermodynamic analysis, the underlying heating mechanism is quantitatively interpreted, which involves high-frequency interparticle friction and plastic deformation driven by ultrasonic squeezing. Consequently, temperature rises rapidly at a speed of about 300 K/s, and the maximum temperature reaches up to 0.9 times of melting point of the aluminum during UAS. The sintered specimens have a high density of dislocations, under the combined effects of dislocations and undulating stress field, volume diffusion coefficient for sintering increases by several orders of magnitude, therefore, rapid densification can be accomplished in seconds. In addition, the sintered aluminum has ultrahigh nanohardness (similar to 1.13 GPa), which can be attributed to the hierarchical structure formed during UAS process.