Microstructural evolution in dissimilar Al/Ti interfaces generated under non-equilibrium conditions by solid-state processing

非平衡条件下固态加工产生的异种 Al/Ti 界面的微观结构演化

• 批准号: 464986536
• 负责人: Professor Dr.-Ing. Benjamin Klusemann
• 金额: --
• 依托单位: Russian Science Foundation
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/464986536?language=en
• 关键词: Microstructural; evolution; dissimilar; Al; Ti

Multi-material structures are possibly the best alternative to achieve structural weight reduction in the transportation sector. Such multi-material structures are currently joined by either adhesive bonding or in form of mechanical connections, such as riveting. The former brings an environmental burden and the latter a weight penalty. Solid-state joining processes are environmental friendly technologies, capable of producing defect free joints in dissimilar material combinations with superior mechanical properties. These processes are characterized by transient temperature cycles (i.e. high heating rates and cooling rates where the maximum temperatures stays below the melting point of the materials being joined) and high strain rates, causing intensive material flow in the joint region. As a result, non-equilibrium structures are formed in the interface of the joints. Such microstructures have been shown to be directly responsible for the mechanical performance of lightweight structures. A few isolated studies in the literature have investigated the microstructure evolution resulting from thermo-mechanical processes typical of solid-state joining processes for specific materials or material combinations. However, no systematic effort is reported on isolating the effects of thermal cycle and material flow on joint formation in dissimilar materials joints. Furthermore, the effect on specific alloying elements on diffusion phenomena and IMC phase formation in interfacial regions is sparsely reported for joints produced by solid-state processes. The present project addresses the above mentioned knowledge gaps in the understanding of microstructural evolution in bi-metallic interfaces generated under non-equilibrium conditions. To achieve this goal, friction stir welding and refill friction stir spot welding will be employed to produce dissimilar overlap joints between experimental Al-Si-Mg alloys (based on the AA6013 composition) and a Ti-6Al-4V alloy, supported by corresponding numerical process simulations. The experimental Al alloys will contain systematically varied alloying contents to allow for the investigation of the effect of these key elements on microstructural evolution.

在交通领域，多材料结构可能是实现结构轻量化的最佳选择。这种多材料结构目前要么通过粘接连接，要么以机械连接的形式连接，例如铆接。前者带来了环境负担，后者带来了沉重的惩罚。固态连接工艺是一种环境友好的技术，能够在不同的材料组合中生产无缺陷的接头，并具有优异的机械性能。这些过程的特点是瞬时温度循环(即高加热速率和高冷却速率，其中最高温度保持在被连接材料的熔点以下)和高应变率，导致连接区域内材料的密集流动。结果，在接头界面形成了非平衡结构。这种微结构已被证明对轻质结构的机械性能有直接影响。文献中一些孤立的研究调查了特定材料或材料组合的固态连接过程中典型的热机械过程所导致的微观结构演变。然而，关于隔离热循环和材料流动对不同材料接头中接头形成的影响的系统研究尚未见报道。此外，对于固相连接，特定合金元素对界面扩散现象和IMC相形成的影响的报道也很少。本项目涉及在了解在非平衡条件下产生的双金属界面的微结构演变方面的上述知识空白。为了实现这一目标，将采用搅拌摩擦焊和再填充搅拌摩擦点焊的方法，在相应的数值模拟支持下，在实验的Al-Si-Mg合金(基于AA6013成分)和Ti-6Al-4V合金之间产生不同的重叠接头。实验铝合金将包含系统不同的合金化含量，以便研究这些关键元素对组织演变的影响。