Eutectic Al alloys with tailored solidification path to probe fundamental aspects of solidification in laser-based AM II

具有定制凝固路径的共晶铝合金，用于探测基于激光的 AM II 凝固的基本方面

• 批准号: 409726740
• 负责人: Dr. Markus Apel
• 金额: --
• 依托单位: Access e.V.
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/409726740?language=en
• 关键词: Eutectic; Al; alloys; tailored; solidification

Our project goal is to evaluate the Al-Ni-Ce system around its zone of coupled eutectic growth for its suitability for PBF-LB/M. In particular, ultra-fine eutectic structures with superior mechanical properties are originally targeted. In phase 1, we have already verified two of our research hypotheses, namely that in Al-Ni the material microstructures, in particular an ultra-fine binary eutectic, can be designed by selecting hypereutectic alloy compositions and specific processing conditions. Indeed, while the spacing has proven efficient to apprehend the solidification velocity in the case of a eutectic coupled growth, a broad range of other microstructures have been evidenced, both experimentally and numerically (phase-field method), illustrating the strong asymmetric coupled zone of eutectic growth. Moreover, the process and material parameters also influence the melt pool dynamics, and a link between its dimensions and the porosity formation via keyholing has been established. In phase 2 of SPP2122, this link will be investigated in more detail. Especially, the influence of the hatch distance and the laser spot size will receive our attention in order to better understand the keyholing onset dependent on alloy composition and thereby broaden the process window, particularly at low laser scanning speed. Melt pool simulations, as well as experiments with the ternary Al-Ni-Ce alloy, will be performed. Reducing porosity goes hand in hand with generating appropriate microstructures. In this respect, the variety of possible microstructures is expected to become even broader in the ternary alloy system than for binary alloys. A particular focus will be put on the three-phase eutectic coupled growth in order to produce ultra-fine ternary eutectics as well as on a two-phase nanocrystalline structure, evidenced during phase 1 for large scanning speeds, with grain sizes in the range of 50 nm for both phases. This nanocrystalline structure emerges intrinsically, shows remarkably large hardness values and no solidification cracks, however, it seems to be prone to cold cracks.We will systematically perform mechanical testing (hardness, tensile tests) on the produced samples when porosity is low and the microstructure is promising. Our project should then provide, at the end of phase 2, a procedure to build dense specimens with, possibly even locally, optimized properties.

我们的项目目标是评估其对PBF-LB/m的适用性耦合共晶增长区域周围的AL-NI-CE系统。特别是，具有优质机械性能的超细共晶结构是针对的。在第1阶段中，我们已经验证了我们的两个研究假设，即在al-Ni中，可以通过选择过度核能合金组成和特定的处理条件来设计材料微观结构，尤其是一种超细二元共晶。的确，尽管在共晶耦合生长的情况下，虽然间距已被证明有效地理解了固化速度，但在实验和数值上（相位磁场方法）已经证明了广泛的其他微观结构，这说明了强烈的不对称偶发区的强烈不对称耦合区。此外，过程和材料参数也会影响熔体池动力学，并且已经建立了其尺寸与孔隙形成的孔隙率之间的联系。在SPP2122的第2阶段中，将对此链接进行更详细的研究。尤其是，舱口距离和激光斑点的影响将受到我们的注意，以便更好地了解取决于合金组成的钥匙门发作，从而扩大过程窗口，尤其是在低激光扫描速度下。将进行熔体池模拟以及对三元素合金的实验。降低孔隙率与生成适当的微观结构并驾齐驱。在这方面，与二元合金相比，预计可能的微观结构将在三元合金系统中变得更广泛。特定的重点将放在三相的共晶耦合生长上，以生产超细节的三元晶体和两相纳米晶体结构，这在大型扫描速度的过程中证明了这两个阶段的50 nm范围。这种纳米晶体结构本质上出现，显示出非常大的硬度值，并且没有固化裂纹，但是，当孔隙率较低并且微观结构有希望时，我们将系统地对产生的样品进行机械测试（硬度，拉伸测试）。然后，我们的项目应在第2阶段结束时提供一个程序，以构建密集标本，甚至可能在本地优化的属性。