Papers by Author: Shi Hong Zhang

Abstract: The precipitation kinetic and behavior of δ phase in Inconel 718 alloy at 900, 930 and 960°C have been studied using the quantitative X-ray diffraction (XRD) method. The results indicated that the nucleation site and way of δ phase depended on temperature by the observation of microstructures. During the aging process, the δ phase nucleated on the grain boundaries and twin boundaries preferentially, while the δ phase precipitated directly from the interior of grain when the temperature was above 900°C. At a certain aging temperature, the relationship between the δ phase content and the aging time fitted an Avrami-type equation.

Abstract: The curves of true stress-strain of AZ80 Magnesium alloy had been tested with thermal simulation experiment, at the conditions of the experimental temperature being 260°C~ 410°C, and strain-rate being 0.001~ 10s-1, and the deformation degree being 50％. According the Arrhenius equation, a kind of constitutive equation of AZ80 Magnesium alloy which considered the strain had been put forward, and the relative errors between calculation results by the stress-strain model and experiment results are less than 10.5%.

Abstract: Magnesium alloy tailor-welded blanks(MTWBs) of AZ31 and AZ80 sheet had been manufactured by gas tungsten arc welded(GTAW), which the thickness were 0.8mm. The welding properties of Magnesium alloy sheet had been analyzed, and the technology parameters of GTAW were determined by experiment study, which was that welding thread being Φ2.0mm, welding electricity 50A, welding voltage 9V, welding rate 12—13cm/min. The research results presented that the grain in welded seam was isometric crystal, and the grains were branching crystal in heat-affected zone (HAZ). For MTWBs of AZ31and AZ80 sheet which the thickness was 0.8mm, the forming parameters were that the forming temperature of AZ31 being 190-220°C, and forming temperature of AZ80 being 310°C-350°C, and the temperature of tools is 180°C~200°C.