Anisotropic shrinkage during hip of encapsulated powder
Anisotropic shrinkage during hip of encapsulated powder
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DOI：
10.1016/j.jmatprotec.2015.06.037
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发表时间：
2015-12
影响因子：
6.3
通讯作者：
C. V. Nguyen;A. Bezold;C. Broeckmann
中科院分区：
文献类型：
--
作者：
C. V. Nguyen;A. Bezold;C. Broeckmann
在P/M HIP中，根据预固结后粉末的初始相对密度，胶囊体积减少到25-30%。在等静压条件下，胶囊应该有一个均匀的收缩，但在实践中往往不是这样。这种现象是由许多因素驱动的，包括但不限于温度梯度、胶囊内粉末的不均匀性和胶囊厚度，这些因素的影响将在本研究中进一步研究。采用实验图像分析方法研究粉末的初始分布，并将其作为初始条件在有限元模型中模拟热等静压制品的形状变化。为了分析胶囊内温度梯度的影响，假设温度在胶囊表面的分布不均匀。然后将不同的温度场应用于有限元模型。此外，胶囊厚度的变化将研究其对最终形状的影响。最后将仿真结果与实验结果进行了比较。在此基础上，得出了粉末分布不均匀、温度梯度和胶囊厚度对粉末HIP-ed产品最终形状的影响。
In P/M HIP, the capsule volume is reduced to 25–30% depending on the initial relative density of the powder after pre-consolidation. Under isostatic pressing conditions the capsule should have a uniform shrinkage, but in practice this is often not the case. This phenomenon is driven through many factors including, but not limited to, the temperature gradient, inhomogeneity of powder inside the capsule and capsule thickness of which the influence will be further examined in this study. Experimental Image Analysis is used to investigate the initial powder distribution which is subsequently implemented in a FEM model as initial condition to simulate the shape changes of hot isostatically pressed products. To analyze the effect of a temperature gradient in the capsule, the temperature is assumed to be inhomogeneously distributed on the surfaces of the capsules. Different temperature fields are then applied to a FEM model. Additionally, capsule thickness will be varied to study its influence on the final shape. Finally the simulation results are compared with experimental findings. Based on that the conclusion about the influence of inhomogeneous powder distributions, temperature gradients and capsule thickness on the final shape of powder HIP-ed products can be given.