Development of digital image processing based methodology to study, quantify and correlate the microstructure and three dimensional fracture surface morphology of aluminum alloy 7050.

摘要

7XXX series wrought aluminum alloys are extensively used for structural aerospace applications due to their high strength to weight ratio, excellent corrosion resistance, and high fracture resistance. 7050 is an important alloy of this group, which is widely used for the applications such as aircraft wing skin structures, aircraft landing gear parts, and fuselage frame structure. Therefore, it is of interest to investigate the fracture behavior of 7050 aluminum alloy, which is a typical alloy of 7XXX series.; The aim of this research is to quantitatively characterize and model the relationships among processing, microstructure, fracture surface morphology, and fracture toughness of hot-rolled partially recrystallized precipitation hardened 7050 alloy. A new technique is developed which permits simultaneous viewing of the fracture surface and the microstructure just below and above the fracture surface. This technique is then applied to identify, validate and quantify various fracture micro-mechanisms observed on the fracture surface. To get a better insight in to the shape and anisotropy of the recrystallized grains, the three-dimensional structure of the microstructure is reconstructed using serial sectioning. The gathered information is utilized to develop a mathematical model relating the various processing parameters and microstructural attributes to the fracture toughness.