Dongyan Ding

Effect of minor cerium additions on microstructure and mechanical properties of cast Al – Cu – Mg – Ag alloy

Abstract A series of cast Al – Cu – Mg – Ag based alloys with minor cerium additions have been investigated using optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and transmission electron microscopy. It was found that increasing the cerium content from 0 to 0.45 wt-% increased the tensile strength at the test temperatures of 25°C and 300°C. The high strength of the casting alloys with cerium is attributed to the refined grains and the high density of fine ω precipitates. However, the addition of 0.2 wt-%Ce to the alloy with 0.25 wt-%Ti induced a detrimental effect on the mechanical properties. The cause of this was found to be the formation of the intermetallic compound Alx Ti6 Ce3 Cu.

Effect of Zr addition on microstructure and properties of Al–Mn–Si–Zn-based alloy

Abstract Effects of Zr addition on the microstructure, mechanical and electrochemical properties of Al–Mn–Si–Zn alloy were investigated. Transmission electron microscopy (TEM) observations reveal that, in as-annealled state, the precipitates in the Zr-containing alloy are finer and more dispersive than those in the Zr-free alloy. Whereas, in simulated brazing state, a weaker precipitation is found in the Zr-containing alloy. Tensile testing results indicate that, with Zr additon, comprehensive mechanical properties of the as-annealed alloys could be significantly improved but weakened for the simulated brazing alloy. Electrochemical testing results reveal that, with Zr addition, the corrosion resistance of the as-annealed alloy decreases. However, after the simulated brazing treatment, such a negative effect of Zr element on the corrosion behavior of the alloy could be negligible.

Effect of Zn content on tensile and electrochemical properties of 3003 Al alloy

The effect of Zn addition on the microstructure, tensile properties and electrochemical properties of as-annealed 3003 Al alloy was investigated through TEM observations, tensile tests and Tafel polarization analysis. High density precipitates are observed in the Zn-containing alloys and the alloy with 1.8% Zn addition also has rod-like precipitates. Tensile test results indicate that Zn has a great effect on tensile strength of 3003 Al alloy. The alloy with 1.5% Zn addition has the highest ultimate tensile strength. The electrochemical results indicate that Zn addition to 3003 Al alloy also has great impact on the corrosion potential of the 3003 Al alloy in 0.5% NaCl solution and ethylene glycol-water solution. The corrosion potential varies with the Zn content and shifts negatively.

Effect of titanium additions on mechanical properties of Al–Cu–Mg–Ag alloy

Abstract The precipitation hardening response, microstructure and mechanical properties of four Al – Cu – Mg – Ag based alloys containing 0, 0.25, 0.6 and 1.1 (wt-%) titanium were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). It was shown that increasing the titanium content from 0 to 0.6 wt-% increased the tensile strength at all test temperatures up to 350°C. The high strength of the alloy with 0.6%Ti is attributed to the high density and high thermal stability of fine ω precipitates and an additional titanium containing intermetallic compound (Al3Ti).