Laser assisted strategies for the manufacturing of property-enhanced Tailor Heat Treated Blanks

本研究项目的目标是确定和鉴定用于生产7000系列高强度、沉淀硬化铝合金的裁剪热处理毛坯(THTB)的辐照策略。基于用于制造THTB的传统的线性-连续热处理布局，将产生新的辐照概念，以改善热处理区域在形状变形和材料性能方面的均匀性。这种方法是基于实验和数值相结合的方法。在第一个工作包(WP)中，研究了材料参数与温度的关系。一方面，热力耦合有限元模型的相关输入参数必须在高温下确定。另一方面，为了模拟THTB的局部适应流动行为，必须研究短期热处理后的力学性能。这些输入参数将用于WP2中的建模。这种方法是基于两步模型的。激光热处理的热机械效应将根据所产生的形状变形和材料特性的分布进行数值模拟。建立了成形过程的力学模拟模型，该模型考虑了材料的流动行为与温度分布和预应变的关系。采用WP2验证的有限元模型，在第三个WP中进行基于有限元的变量计算，以确定不同的定量和定性因素对形状变形和热处理均匀性的控制变量的影响。将开发新的热处理策略。数值计算结果将通过实验研究得到验证。根据这些结果，将进行显着性检验，以确定最具影响的因素。最后一项工作集中于对WP-2有限元模型的第二步进行验证，以及该模型在THTB工艺设计中的应用。在数值计算和实验结果的基础上，对演示台的几何形状进行了局部激光热处理，然后进行了拉深加工。最终零件的数字化使成形模拟的实验验证以及关于所产生的部件性能的不同热处理概念的比较成为可能。与传统的线性-连续激光热处理相比，新的辐照概念的应用必须改善性能。将WP-3中的替代热处理概念应用的一般指南转移到演示器的几何形状上，可以对结果进行鉴定。

The objective of the present research project consists of the identification and qualification of irradiation strategies for the production of Tailor Heat Treated Blanks (THTB) of high strength, precipitation hardenable aluminum alloys of the 7000 series. Based on conventional, linear-continuous heat treatment layouts for the manufacturing of THTB, new irradiation concepts will be derived in order to improve the homogeneity of the heat treated area with respect to shape distortion as well as material properties. This approach is based on a combined experimental-numerical methodology. In the first work package (WP) temperature-dependent material parameters are investigated. On the one hand the relevant input parameters for a thermo-mechanical coupled FE-model have to be determined at elevated temperatures. On the other hand mechanical properties after a short-term heat treatment have to be investigated in order to model the locally adapted flow behavior of THTB. These input parameters will be used for modeling in WP2. This approach is based on a two-step model. The thermo-mechanical effect of a laser heat treatment will be modeled numerically with respect to the resulting shape distortion as well as the distribution of material properties. A mechanical simulation model for forming processes will be developed, which considers the material flow behavior in dependency of temperature distribution and pre-straining. A FE-based calculation of variants will be carried out in the third WP using the validated FE model from WP2 to identify the influence of different quantitative as well as qualitative factors on the command variables of shape distortion and homogeneity of the heat treatment. New heat treatment strategies will be developed. The numerical results will be verified by experimental investigations. Based on these results a significance test to identify the most influencing factors will be carried out. The last work package focuses on the validation of the second step of the FE-model from WP 2 as well as the application of the model for the process design of THTB. Based on numerical and experimental results a local laser heat treatment will be carried out for a demonstrator geometry, followed by a deep-drawing process. The digitalization of the final part enables the experimental validation of the forming simulation as well as the comparison of different heat treatment concepts regarding the resulting component properties. The application of new irradiation concepts has to improve the properties compared to a conventional, linear-continuous laser heat treatment. The transfer of the general guidelines for the application of alternative heat treatment concepts from WP 3 on the demonstrator geometry enables the qualification of the results.