多元合金高温熔池固-液界面热扩散行为

项目名称： 多元合金高温熔池固-液界面热扩散行为

项目编号： No.51206010

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 工程热物理与能源利用学科

项目作者： 童莉葛

作者单位： 北京科技大学

项目金额： 25万元

中文摘要： 焊接过程是一个复杂的、非平衡的、强非线性的耦合热质传递过程，具有快速连续加热冷却的特点。对热循环条件下固-液界面多元素高温热扩散及耦合作用特性的研究是以揭示多场耦合驱动的能质传输与合金物相转化为目标，本申请将围绕"多元合金高温熔池多场耦合热质传输机制"这一关键科学问题，建立考虑Marangoni效应的逐层填充熔池传热数学模型，研究熔池内金属熔体的流动行为和熔池的演变规律，获得固-液界面的移动规律。通过制备固-液自由扩散偶研究不同熔池条件下单一元素的扩散-溶解层的厚度、生长规律与元素含量；实验研究固-液界面多元素高温热扩散耦合行为，使用关联系数法解析多元合金元素热扩散的耦合作用表征参数，揭示熔池金属元素热扩散的主导因素，开展高温熔池固-液界面能质传输与合金物相转化规律、热循环条件下高温熔池的溶质扩散规律等方面的研究，为焊缝与熔合区的品质调控、成分预测和工艺优化提供重要的理论支撑。

中文关键词： 熔池；扩散；热质传递；Marangoni效应；相变

英文摘要： The welding process is usually subjected to a continuous heating and cooling cycle with inherent complexities, such as large material property variation, phase transformation and complex boundary condition, combined with heat and mass transfer coupling. Under thermal cycling condition, thermal diffusion characteristic of multi-element on solid-liquid interface at high temperature is studied to carry out heat and mass transmission where the multi-field drive force and phase transformation of alloy is coupled. The key problems of the application will be solved "heat and mass transfer mechanism of multi-alloy with multi-field drive force at high temperature molten pool". Considering the Marangoni effect, the heat transfer mathematical model filling layer by layer in molten pool is established to study the flow behavior and the evolution of the molten pool for welding process and to get the movement rule of the solid-liquid interface. Single element and alloy diffusion melting layer thickness, and distribution of the element content will be achieved by experimental research on preparing solid-liquid free diffusion couple under different conditions. The heat diffusion coefficient of multiple-alloy elements and the coupling parameters can be calculated by using correlation coefficient method. The dominant factor of t

英文关键词： melting zone；diffusion；heat and mass transfer；Marangoni effect；phase transformation