نوع مقاله : مقاله پژوهشی
نویسندگان
1 مواد و متالورژی، صنعتی امیرکبیر، تهران
2 گروه فرایندهای ساخت- دانشکده مهندسی مواد و متالورژی-دانشگاه صنعتی امیرکبیر
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
The distance of the secondary dendritic arms is an important microstructural feature in the dendritic solidification and has a great influence on the hardness of the alloy, and the main factor affecting it is the cooling rate. Due to the difficulty of its practical measurement, numerical methods should be used to predict it. In this study, first, 3 samples were produced with current of 95, 120 and 132. Then, using the results of the validated model, a 3D finite element model was developed to generate welding profiles and analyze transient heat transfer, and the cooling rate at different points of the weld metal was calculated. The model outputs (cooling rates, thermal gradient G and growth rate R) were used to describe the solidification structures. It was found that for the sample produced with current of 95 A, the cooling rate was between 650 K.S-1 to 800 K.S-1, but for the sample produced with a current of 132 A, the cooling rate was between 270 K.S-1 to 350 K.S-1. Then, using optical microscopy, the distance of the secondary dendritic arms in different regions was measured on the sample produced from the IN738LC superalloy, and the constants a and n in the mathematical relationship between the distance of the secondary dendritic arms and the cooling rate were obtained, which were equal to 34.62 and 0.3, respectively.
کلیدواژهها [English]
)