Comparison of precipitation kinetics and mechanical properties in Zr and Sc-bearing aluminum-based alloys

The effect of Al8Cu4Er phase on the corrosion behavior of Al–Cu–Mg alloy with rare earth Er addition in an under-aging state was studied. The results revealed that the addition Er into the Al–Cu–Mg alloy induced the formation of Al8Cu4Er phase. The Al8Cu4Er phase can significantly refine the grains during recrystallization, thereby suppressing the continuous precipitation of S-phase at grain boundaries and improving the resistance to intergranular corrosion. Conversely, the corrosion susceptibility of local regions around the Al8Cu4Er phase with large dimension was higher than that of the AlCuFeMnSi phase, but weaker than that of θ phase, resulting in decreased pitting corrosion resistance.

Effects of Al8Cu4Er Phase on Corrosion Behavior of Al–Cu–Mg alloy with Er addition

The precipitation behavior and mechanical properties of cast Al-4.5Cu-3.5Zn-0.5Mg alloy

The background of this paper is a new type of heat-resistant alloy for aviation. In allusion to the defects in Al6Cu2Ni alloy castings, the defects were removed by milling and repaired by arc adding. The results show that the grain distribution in the weld is uniform and there is no delamination. The orientation of the grains in the weld is disordered and the crystal structure is stable with a large angle. The composition of the second phase in the weld metal is the same as that of the base metal, and no new phase is formed. Al3CuNi, Al7Cu4Ni, and Al2Cu were formed and concentrated at the grain boundary, and AL3M existed in micron size. The tensile strength at room temperature is 213.8 MPa, the yield strength is 159 MPa, the elongation is 1.65%, and the tensile property is 93% of the base metal. There are a lot of cleavage surfaces on the fracture surface, which is a typical brittle fracture. 

Microstructure and properties of Al6Cu2Ni gearbox with TIG additive for repairing casting defects

A new Al–Cu–Ni alloy was repaired by arc additive remanufacturing and T6 heat treatment. The results show that the grain size in the upper part of the weld is slightly larger than that in the lower part, and the whole distribution is uniform without delamination. The orientation of grains in the weld is disordered, and most of them are stable crystal structures with a large angle. The average tensile strength at 300°C is 148.3 MPa, the yield strength is 106.6 MPa and the elongation is 10.5%. δ-Al3CuNi and γ-Al7Cu4Ni increase the strength of grain boundary, and the strength of θ″ and θ′ are dispersed from the α-Al matrix during aging, which are the main reasons for obtaining high-temperature properties.

Arc additive remanufacturing of a new type of Al–Cu–Ni aviation case: microstructure and high-temperature properties under T6 heat treatment

Alloying with rare earth metals improves to the mechanical properties and corrosion resistance of aluminium base alloys at high temperatures. The rare earth metal erbium may be used for grain refinement. Within a project of computer-aided alloy development based on the CALPHAD (CALculation of PHAse Diagrams) method various alloys were melted on the Al-rich side of the ternary system Al-Cu-Er under argon atmosphere and their microstructures were characterized in the as-cast state or after long-term isothermal annealing (400°C/960 h) by means of different investigation techniques. As a result, the phases fcc(Al), τ1-Al8Cu4Er, θ-CuAl2, η-CuAl, and Al3Er were identified, their compositions and fractions were quantified, and their hardnesses were determined. The experimental obtained microstructures agree very well with the calculated solidification behaviors of the cast alloys. The knowledge gained from this work about the phase compositions and microstructures can also be utilized for the fine optim...

Z. Jin

Papers

Microstructures of Erbium Modified Aluminum-Copper Alloys