Tóm tắt Luận án Tiến sĩ: Nghiên cứu độ bền và cơ chế phá hủy của mối hàn ma sát giữa hợp kim nhôm AA6061-T6 với thép không gỉ SUS316

In various advanced industrial sectors such as aerospace, automotive, and marine, the demand for lightweight yet high-strength structures necessitates innovative joining techniques for dissimilar materials. Welding aluminum alloys like AA6061-T6 with stainless steel such as SUS316 presents significant challenges due to their inherent differences in physical and chemical properties, often leading to issues like brittle intermetallic compound (IMC) formation and welding defects with traditional fusion methods. Friction Stir Welding (FSW) stands out as a promising solid-state joining technology capable of mitigating these problems. This study comprehensively investigates the mechanical strength, fracture mechanisms, and corrosion behavior of FSW joints between AA6061-T6 aluminum alloy and SUS316 stainless steel, aiming to provide critical insights for optimizing welding processes and enhancing material performance in diverse operational environments.

Các nhà nghiên cứu và kỹ sư trong lĩnh vực khoa học vật liệu, kỹ thuật cơ khí, công nghệ hàn, cũng như các chuyên gia trong ngành hàng không, ô tô và hàng hải quan tâm đến việc hàn vật liệu khác loại và chống ăn mòn.

This doctoral thesis provides an in-depth examination of the strength and fracture characteristics of **Friction Stir Welded (FSW)** joints formed between **AA6061-T6 aluminum alloy** and **SUS316 stainless steel**. Addressing the complexities of joining these **dissimilar materials** with distinct properties, the research focuses on understanding how various **welding parameters**—including rotational speed, welding speed, pin plunge depth, and pin length—impact the joint's microstructure and mechanical performance. The methodology combines a thorough theoretical review with extensive experimental investigations, involving the fabrication of FSW joints and detailed analyses of their microstructure, specifically grain structure, thickness of intermetallic compound (IMC) layers, and diffusion layers, alongside microhardness and tensile strength evaluations. A significant aspect of the study is the comprehensive investigation into the **corrosion behavior** of these joints across different aggressive environments, encompassing variations in NaCl concentration, applied electrochemical potential, and temperature, to elucidate the underlying **corrosion mechanisms**. The findings significantly contribute to the academic understanding of **dissimilar material welding** and the **fracture mechanisms** and **corrosion resistance** of FSW joints. Practically, this research offers invaluable data for optimizing **welding parameters** to achieve superior **joint strength** and durability. The insights gained are particularly relevant for industries such as aerospace, automotive, and marine, where the demand for lightweight, high-performance, and corrosion-resistant components is paramount, thereby fostering more advanced and reliable manufacturing solutions.