Chen Zhiguo

Influence of Ce on Microstructure and Properties of High-carbon High-boron Steel

Abstract The influence of Ce on the microstructure and the properties of high-carbon high-boron steel (HCHBS) were investigated by optical microscopy (OM), scanning electronic microscopy (SEM), and X-ray diffraction (XRD). The results indicate that the impact toughness and the wear resistance of the HCHBS can be significantly enhanced by adding of Ce, whereas the addition of Ce has no obvious effect on hardness. After being modified by Ce, the primary austenite grains of the HBHBS are greatly refined and most of the fishbone-like and lamellar borocarbides transform into blocky and granular borocarbides; meanwhile, the distribution of borocarbides becomes more uniform.

Effects of trace silver and magnesium on the microstructure and mechanical properties of Al−Cu−Li alloys

The effects of trace silver and magnesium additions on the microstructure and mechanical properties of the Al−Cu−Li alloys were investigated. The experimental results indicate, that the effect of combined additions of Ag and Mg is the most obvious, the next is that of individual addition of Mg, and that of individual addition of Ag is the least. The addition of Ag and Mg in Al−Cu−Li alloy accelerates the precipitation of T1 and results in increasing the ageing hardness and strength. Prior cold work significantly improves the tensile strength by enhancing T1 precipitation in all the alloys investigated.

Processing Maps for Controlling Microstructure of an Aircraft 2E12 Aluminum Alloy

Abstract The deformation behavior and microstructure evolution in a hot compressed 2E12 alloy was investigated by constructing power dissipation map in which work efficiency can be related with microstructure evolution. Compression tests were performed in the temperature range of 250–500 °C and the strain rate ranging from 0.01 s−1 to 10 s−1 up to a true strain of 0.5. The processing maps reveal that two domains where dynamic recovery occurs comparatively: (1) 325–400 °C and 0.01–0.03 s−1, (2) 350–450 °C and 1.78–10 s−1, and partial dynamic recrystallization occurs at T≥450 °C. However, there also is evidence of redissolution of the particles and intercrystalline cracks at 500 °C and 1–10 s−1. It is shown that the volume of partial recrystallization increase with increasing of deformation temperature.

Regulation Mechanism of Novel Thermomechanical Treatment for Microstructure and Properties of 2E12 Aluminum Alloy

Abstract The effects of a novel thermo-mechanical treatment (TMT) on the mechanical properties and the microstructure of 2E12 aluminum alloy were investigated by tensile test and fatigue crack propagation test, as well as scanning electron microscope and transmission electron microscope (TEM). Results show that a good combination of strength and plasticity can be achieved for 2E12 aluminum alloy by the new TMT, the yield strength increases by ∼28% over that of T3, and the ultimate tensile strength also increases by 17%, while the high elongation of T3 condition (over 16%) is maintained. The fatigue crack growth rate of the TMT is lower than those of the T3 and T6 peak aged samples. A high density of tangled dislocation is contained in the TMT 2E12 aluminum alloy, and dislocation cell substructure is formed. The mechanism of the new TMT technique, by which the mechanical properties of the alloy is greatly increased, is the synergistic effect of composite structures, including dislocation cell substructures, the complex of Mg/Cu/vacancies, as well as GPB zones.