The University of Osaka · 공학
다니엘로 암브로시오 교수의 연구실은 마이크로구조 제어와 열기계적 거동 분석을 중심으로 한 고성능 Friction Stir Welding(FSW) 기술 개발에 집중하고 있습니다. 특히 알루미늄 합금, 스틸, 티타늄 합금 등 다양한 재료 간의 이종접합을 위한 FSW 공정 최적화 및 결함 예측 기술 개발이 핵심 연구 주제입니다. 기계학습 기반 결함 진단, 열전달 모델링, 특수 형상의 용접 툴(예: 구형 툴, 기울인 툴)을 활용한 재료 유동 제어 기법 등 응용 기술 개발도 활발히 진행되고 있습니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
The dissimilar friction stir lap welding of AA6061-T6 and mild steel using the hemispherical tool tilted towards the retreating side is investigated. Critical defects such as hook features and internal voids are avoided by limiting the plunge depth in the lower plate to a tenth of a millimeter. The low heat generation guaranteed by the hemispherical tool produces a nanoscale intermetallic compound layer alternatively composed of an Al-rich and a ternary Al-Fe-Mg phases. The complex and extremely
Abstract In this work, the friction stir weldability of Ti6Al4V T-joints has been investigated. Its aims are: (i) to study the influence of tool and welding parameters on weld quality, (ii) to assess the joints’ mechanical strength to foresee future applications, and (iii) to characterize Co-based FSW tools’ wear by following the wear during the tests. Welds’ defectivity is studied by cross-section macrographies analysis. Independently from welding parameters and tools, internal voids are avoide
Abstract Flow-related defects in friction stir welding are critical for the joints affecting their mechanical properties and functionality. One way to identify them, avoiding long and sometimes expensive destructive and nondestructive testing, is using machine learning tools with monitored physical quantities as input data. In this work, artificial neural network and decision tree models are trained, validated, and tested on a large dataset consisting of forces, torque, and temperature in the st
Process parameters and base material thermal properties strongly affect peak temperature evolution in friction stir welding (FSW). This work develops a semi-empirical model for peak temperature estimation during FSW of aluminium alloys. Several bead-on-plate runs were conducted on AA5083-H111, AA6082-T6 and AA7075-T6. Different rotational and welding speeds were tested while measuring the temperature with a thermocouple embedded in the tool. A polynomial model was proposed with the model's coeff
The use of a hemispherical tool tilted towards the retreating side for friction stir welding 6061-T6 aluminum alloy is investigated. Joints with smooth surfaces and without internal voids are obtained. Under the same welding and rotational speeds, adapting the tilt angle makes it possible to weld various thicknesses up to 3.5 mm. Plunge depth and tilt angle are demonstrated to be key geometrical parameters driving material flow when using the hemispherical tool. Microstructural features in the w
Abstract This paper describes a thermal numerical model accessible to all users for predicting temperature in friction stir welding from the power, material thermal properties, process parameters, tool, and plate dimensions. Starting with the information obtained from the machine, power or torque, the heat flux is modeled as a circular moving source with a diameter equal to that of the shoulder. The model calibrated in a specific setup (CNC machine) successfully predicted without recalibration t
