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

本研究项目的目标包括确定和确定辐照策略，以生产高强度、可沉淀硬化的7000系列铝合金定制热处理毛坯（THTB）。基于传统的、线性连续的热处理布局来制造THTB，新的辐照概念将被衍生出来，以改善热处理区域在形状畸变和材料性能方面的均匀性。这种方法是基于实验与数值相结合的方法。在第一个工作包（WP）中，研究了与温度相关的材料参数。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，短期热处理后的力学性能必须进行研究，以便模拟THTB的局部适应流动行为。这些输入参数将用于WP2中的建模。这种方法基于两步模型。激光热处理的热机械效应将根据产生的形状畸变和材料特性的分布进行数值模拟。建立了一种考虑温度分布和预应变对材料流动行为影响的成形过程力学模拟模型。在第三个WP中，将使用WP2中验证的有限元模型进行基于有限元的变量计算，以确定不同定量和定性因素对热处理形状畸变和均匀性的命令变量的影响。新的热处理策略将被开发出来。数值结果将通过实验研究得到验证。基于这些结果，将进行显著性检验，以确定最重要的影响因素。最后一个工作包的重点是对WP 2中第二步有限元模型的验证，以及该模型在THTB工艺设计中的应用。基于数值和实验结果，将对演示几何图形进行局部激光热处理，然后进行深拉深加工。最终零件的数字化使成形模拟的实验验证以及对不同热处理概念对所得到的部件性能的比较成为可能。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其性能。从WP 3转移到演示器几何形状上的替代热处理概念应用的一般指导方针使结果能够得到确认。

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.