爆炸粉末烧结微孔隙塌缩沉能分析

Analysis of Energy Deposition Caused by Micro-Void Collapse in Explosive Consolidation of Powders

对爆炸粉末烧结过程中颗粒间的结合和沉能机制进行了分析,用反映微孔隙闭合的一维球对称塌缩模型对爆炸粉末烧结后期由微孔隙闭合引起的沉能现象进行了研究。在球对称塌缩一维流动的控制方程中引入传热项的影响,采用刚塑性假设并引入热粘塑性本构关系,利用有限差分法对球壳收缩过程中的温度分布进行了计算。结果表明:热传导的影响随孔隙尺度的变小而变大;球壳收缩过程中其内壁经历了从弹塑性体到流体的转变,其温升远高于其它部位的温升,其它部位较低的温度将对熔化的球心起到低温淬火作用。

The mechanism of distortion and energy deposition at the interface of the particles in explosive consolidation of powders is analyzed. A one-dimension model of spherical symmetry is used to describe the closure of the micro-holes in powders. Effect of heat conduction is added to the one-dimensional flow equations of spherical symmetry, and the temperature distribution during the closure of the hollow sphere is solved by finite-difference under the condition that the material is rigid-plastic fluid and the constitutive equations are thermo-visco-plastic. The results show that effect of heat conduction becomes more remarkable when the scale of the holes become small; during the closure of the holes the state of the interior surface changes from elastic-plastic to fluid, and its temperature is much higher than other part of the spherical shell.