【作者】 张龙； 张晓敏； 褚钟祥；

【Author】 Zhang Long;Zhang Xiaomin;Chu Zhongxiang;College of Aerospace Engineering,Chongqing University;

【机构】 重庆大学航空航天学院；

【摘要】 放电等离子烧结是直接将脉冲大电流直接加在上下压头和模具上,从而实现对粉末颗粒的快速烧结成型的工艺,针对烧结非导电2 3Al O粉末具有小尺度、短时程、高温度梯度和高温升率的特点,本文提出基于非Fourier热传导的热力耦合传播模型,并建立无量纲化的等径两球颗粒三维广义热力耦合方程及相应的初边值条件,用直接有限元方法在时间域和空间域进行求解,得到脉冲电流作用下非导电2 3Al O粉体烧结过程中的温度场分布规律。计算结果表明,热在颗粒中是以有限速度传播,由于波动性,在两球接触部位产生叠加,形成局部高温从而形成烧结颈部,进而实现快速烧结,还给出了接触部位最高温度随球心距的变化曲线,最高温度随球心距的增大而减小,说明在烧结初期,颈部接触面小的颗粒的升温高于颈部接触面大的颗粒。更多还原

【Abstract】 A pulse electric current is applied directly to the graphite mold and punches in spark plasma sintering(SPS),so as to realize rapid sintering molding of powder particles.For sintering the non-conductive powder process with the characteristics of small size,short range,high temperature gradient and high temperature rise r ate,in this paper,based on non Fourier heat conduction coupled thermo-mechanical propagation model,the dimensionle ss two ball diameter particles 3d generalized thermodynamic coupling equations and the corresponding initial boundary value conditions are established,the finite element control equations were solved directly in the time and space domain.The temperature distribution was obtained.The results show that temperature wave speed is limited in the particles,and the wave stack s in the contacting parts,produces local high temperature at sintering neck.In addition,thehighest temperature of sintering neck decreases with increasing of sphere centre distance.更多还原