Affiliation:
1. Research Institute of Automobile Parts Technology, Hunan Institute of Technology, Hengyang 421002, China
2. School of Intelligent Manufacturing and Mechanical Engineering, Hunan Institute of Technology, Hengyang 421002, China
Abstract
In order to explore the hot deformation behaviors of the as-cast 7005 aluminum alloy, a number of hot tensile tests with four temperatures (100, 200, 300, and 400 °C) and three strain rates (0.001, 0.01, and 0.1 s−1) were performed. The Johnson–Cook model was used to express the relationship between stress, strain, strain rate, and temperature. Scanning electron microscopy (SEM), optical microscopy (OM), and transmission electron microscopy (TEM) were selected to reveal fracture features and microstructure evolution of the studied alloy. The results indicate that the flow stress level of the alloy reduces with increases in the deformation temperature and decreases in the strain rate. The established Johnson–Cook model can be employed to characterize the thermal flow behavior of the experimental alloy. The grains near the fracture surface were elongated, and a certain number of holes were found after deformation at 400 °C. The alloy exhibits obvious ductile fracture features. The dimple is deep with high quantity. Due to the plastic deformation, a high-density dislocation structure is found in the material. High-temperature conditions promote the annihilation of dislocation, and, as a result, the dislocation density decreases gradually with the increase in temperature. In addition, a certain number of precipitates were found in the alloy after high-temperature tension.
Funder
the National Natural Science foundation of China
the Scientific Research Fund of Hunan Provincial Education Department of China
the College student innovation and entrepreneurship project
the Aid Program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province
Subject
General Materials Science,Metals and Alloys