Development of high-strength AlZnMgCu-castalloys for light weight constructions - studies of mechanisms of hot tearing formation during solidification

用于轻质结构的高强度 AlZnMgCu 铸合金的开发 - 凝固过程中热撕裂形成机制的研究

• 批准号: 275013255
• 负责人: Professorin Dr.-Ing. Babette Tonn
• 金额: --
• 依托单位: Abteilung Gießereitechnik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/275013255?language=en
• 关键词: Development; strength; AlZnMgCu; castalloys; light

For the objective of reducing the fuel consumption and the subsequent reduction of polluting emissions the automotive as well as the aviation industry have to choose innovative approaches in light-weight construction, which are connected with the development of new light-weight materials. In this perspective high strength AlZnMgCu-alloys with ultimate tensile strength above 600 MPa have a very high development potential.Nowadays, AlZnMgCu-alloys are mainly used as forging alloys, because these materials are very sensitive to hot cracks which limits their ability for the usage of gravity die casting or high pressure die casting. By accurately knowing the mechanisms of the formation of hot cracks in AlZnMgCu-alloys it will be possible to improve their behavior and to establish these alloys as trendsetting casting material for light weight construction.The submitted research project consists of five sub-ordinate targets:1. It will be investigated if the thermal analysis with two thermocouples is a proper method to predict the end of mass respectively interdendritic feeding in AlZnMgCu-alloys by the determination of the Dendritecoherence- and the Rigiditytemperature. This will be accomplished by the comparison of the results of thermal analysis and those of rheological testing.2. A measurement device will be constructed which allows to measure the start temperature of solidification contraction, the start temperature of the formation of contraction strains as well as the temperature of hot cracks in AlZnMgCu-alloys.3. The hypothetical assumptions for the calculation of CSC- and TFR-criteria should be replaced with experimental profound knowledge of the Dendritecoherence- and the Rigiditytemperature. The resulting improvement of CSC- and TFR-criteria will make it possible to predict the hot crack tendency of an (AlZnMgCu-) alloy.4. It will be investigated by thermodynamic calculation of solidification paths if there are other criteria than CSC and TFR for the prediction of hot crack tendency, for example the magnesium content of the residual melt at the end of solidification or the calculated amount of eutectic phases.5. Another focus is the comprehensive investigation of the influence of casting parameters (mould and casting temperature) and grain refinement for the formation of hot cracks. This will result in new high strength aluminum alloys for light weight construction on the basis of AlZnMgCu with excellent hot crack stability.

为了减少燃料消耗和随后减少污染排放的目标，汽车和航空工业必须选择创新的方法在轻量化建设，这与新的轻量化材料的发展有关。从这个角度看，极限抗拉强度在600 MPa以上的高强度alznmgcu合金具有很高的发展潜力。目前，alznmgcu合金主要用作锻造合金，因为这些材料对热裂纹非常敏感，这限制了它们在重力压铸或高压压铸中的应用。通过准确地了解alznmgcu合金热裂纹形成的机制，将有可能改善它们的行为，并将这些合金建立为轻量化结构的铸造材料。提交的研究项目包括五个次级目标：1。本文将探讨用两个热电偶热分析是否可以通过测定枝晶一致性和刚度温度来预测alznmgcu合金中质量枝晶间喂入的结束。这将通过热分析结果和流变测试结果的比较来完成。构建一种测量装置，用于测量alznmgcu合金的凝固收缩开始温度、收缩应变形成开始温度和热裂纹温度。计算CSC-和tfr -准则的假设假设应该被对枝晶相干和刚度温度的深刻实验知识所取代。CSC-和tfr -准则的改进将使预测（AlZnMgCu-）合金的热裂倾向成为可能。如果有比CSC和TFR预测热裂倾向的其他标准，例如凝固结束时残余熔体的镁含量或共晶相的计算量，则将通过凝固路径的热力学计算进行研究。另一个重点是全面研究铸造参数（模具和铸造温度）和晶粒细化对热裂纹形成的影响。这将导致在具有优异热裂稳定性的AlZnMgCu的基础上，产生用于轻量化结构的新型高强度铝合金。