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.

为了减少燃油消耗和随后的污染排放，汽车和航空业必须选择与新轻重量材料的开发相关的轻量重量结构中的创新方法。从这个角度来看，高于600 MPa的最终拉伸强度的高强度ALZNMGCU合金具有很高的发育潜力。如今，Alznmgcu-Alloys主要用作锻造合金，因为这些材料对热裂缝非常敏感，这限制了其对雷神死亡铸造或高压铸造的使用能力。通过准确了解Alznmgcu合金中热裂纹形成的机制，可以改善其行为，并将这些合金确立为轻质重量构造的趋势式铸造材料。提交的研究项目由五个次级目标组成：1。 如果使用两个热电偶的热分析是通过确定树突状和刚性晶状体的质量分析的质量分析方法，可以研究使用两个热电偶的热分析。这将通过比较热分析结果和流变测试的结果来完成。2。 将构建一个测量装置，以测量凝固收缩的起始温度，收缩菌株形成的起始温度以及Alznmgcu-Alloys中的热裂纹温度。3。 计算CSC和TFR标准的假设假设应被对树突状的实验性深刻知识和刚性刚度的实验性知识所代替。 CSC和TFR标准的改善将使预测（Alznmgcu-）合金的热裂纹趋势4。 如果除CSC和TFR以外的其他标准以预测热裂纹趋势，例如，固化趋势（例如，在固体结束时残留熔体的镁含量或Eutectic阶段的计算量）5。 另一个重点是对铸造参数（霉菌和铸造温度）的影响以及对热裂纹形成的晶粒的影响的全面研究。这将导致新的高强度铝合金，以良好的热裂纹稳定性为基础Alznmgcu。