利用ANSYS有限元模拟软件,建立了激光熔凝RuT300三维实体有限元模型,考虑了激光吸收率、材料热物性参数及相变潜热的影响,通过分析不同预热温度下激光熔凝的瞬态温度场,获得预热温度对温度分布、温度梯度、冷却速率等的影响规律。结果表明,随着预热温度的增大,试样相同位置处的最高温度增大,预热温度对试样下部的温度场影响更明显;随着预热温度的增大,试样相同位置处的温度梯度减小,当距离试样上表面的深度达到约2 mm时,试样的温度梯度受预热温度的影响不明显;对试样进行预热处理可降低试样的冷却速率,冷却速率随着预热温度的增大而减小。

Based on the ANSYS finite element simulation software, a three-dimensional solid finite element model of laser melting RuT300 is established, in which the effects of laser absorption rate, thermophysical parameters of materials and latent heat of phases are all considered. The effect law of preheating temperature on temperature distribution, temperature gradient, cooling rate, and so on is obtained by the analysis of the transient temperature fields of laser fusion under different preheating temperatures. The results show that the maximum temperature at the same position increases with the increase of preheating temperature. The preheating temperature has a more obvious influence on the temperature field at the low part of the sample. With the increase of preheating temperature, the temperature gradient at the same position of the sample decreases. When the depth from the upper surface of the sample is about 2 mm, the temperature gradient of the sample is not obviously influenced by preheating temperature. In addition, the preheating treatment of samples can be used to reduce their cooling rates, and it is found that the cooling rate decreases as preheating temperature increases.