PL235538B1 - High-zinc aluminum alloy - Google Patents

Description

The subject of the invention is a zinc-rich aluminum alloy, used for making shaped castings with increased strength and increased tribological and damping properties.

In an article by S.B. Chikalthankar, D.P. Narmala, V.M. Nandedkar Fri "Effect of Silicon Carbide Content on Tribological Properties of Aluminum Zinc Alloy Composite at Elevated Temperature", International Journal of Scientific Engineering and Applied Science (IJSEAS), Volume 1, Issue 4, July 2015, pp. 389-396, the results of the impact study are presented silicon carbide content on the tribological properties at elevated temperature of an aluminum alloy with increased abrasion resistance, which contains by weight: 25.0% zinc, 2.5% copper and 6-9% silicon carbide.

The publication US2013209311A1 discloses the composition of an aluminum alloy which contains by weight: 26-40% zinc, 1-5% copper, 4-13% silicon, the rest of the aluminum and unavoidable impurities. This alloy is intended for electrical, electronic or mechanical components.

Moreover, it is known from the publication CN105441752A an aluminum alloy containing by weight: 4.6-5.3% zinc, 1.0-1.2% magnesium, 0.32-0.44% copper, 0.7-0.75% silicon , 0.13-0.14% iron, 1-2% titanium, 0.1-1.0% nickel, 0.2-1.0% cobalt, 0-0.03% manganese, 0-0.03 % chromium, 0-0.02% gallium, 0-0.02% vanadium, 0-0.02% zirconium, 0-0.03% impurities, the rest of aluminum, and a total manganese and chromium content less than or equal to 0.03 %.

The Russian publication RU2553781C1 describes an alloy of increased strength, containing by weight: 8-10% zinc, 2-3% magnesium, 1.6-2.6% copper, 0.12-0.25% scandium, 0.06- 0.20% zirconium, 0.0001-0.005% beryllium, 0.05-0.15% cobalt, 0.5-1.0% nickel, 0.45-0.95% iron, the rest aluminum.

The Korean publication KR20160068005A discloses a high-strength aluminum alloy for die casting, which in its composition contains: 7.5-8.0% silicon, 9.0-10.0% zinc, max. 3.0% copper, max. 0.15% Magnesium, Max 0.25% Manganese, Max 0.05% Titanium, Max 0.05% Tin, Max 1.0% Iron, 0.05% Rhenium, Rest aluminum.

An aluminum alloy is also known from the patent application No. JPS5861246A, which contains by weight: 80-90% aluminum, 0-20% zinc, 0-10% copper, 0-10% magnesium, 0-5% titanium, 0-3% manganese and 0-2% iron. Stop at the above. composition, after melting, it is pressure cast into a metal mold, and after taking out, the casting is quickly cooled in water or heated to a temperature of 250-300 ° C, and then cooled in water. The aluminum-based alloy in question is superplastic and has favorable strength and vibration damping properties.

In the industrial practice so far, high-zinc aluminum alloys with the simultaneous addition of copper, titanium and an increased addition of manganese have not been used. Previous studies have shown that the addition of Cu in an amount of about 4-5% by weight causes dimensional instability of the casting in a long period, even up to about 2 years after casting. The reason is the presence in the structure, apart from the solution, of the ε CuZns phase, the transformation of which into the stable T 'phase with the composition Al5Cu4Zn is accompanied by dimensional changes that can even reach 4%. On the other hand, limiting the addition of Cu to the level at which the ε phase does not form causes a drastic decrease in strength and tribological properties. In current practice, elevated silicon additions are introduced into high-zinc aluminum alloys as copper substitutes.

A high-zinc aluminum alloy containing, by weight, 1.5-3.5% copper, 0.001-0.2% titanium, 0.2-1.5% manganese and zinc, has a 27.0-45 0% zinc and 0.01-0.5% at least one element selected from the group consisting of chromium, silicon, iron, magnesium, nickel with the rest being aluminum.

The addition of manganese to the alloy composition causes that it partially takes over the role of copper, causing favorable changes in properties, in particular in strength and tribological properties. In turn, the addition of titanium has a positive effect on the plastic properties of the alloy, which has a stable structure that does not show dimensional changes.

Example I

The alloy includes by weight; 2.5% Cu, 0.001% Ti, 0.49% Mn, 27.0% zinc, 0.01% Fe and 70.0% aluminum. The said alloy, after casting into a sand mold, exhibits the following properties:

- tensile strength Rm = 320 MPa

- relative elongation A5 = 1.95%

By comparison, an alloy containing no manganese added has the following properties:

- tensile strength Rm = 265 MPa

- relative elongation A5 = 1.60%

PL 235 538 B1

Example II

The alloy contains by weight: 2.68% Cu, 0.01% Ti, 0.8% Mn, 27.0% zinc, 0.01% Fe and 69.5% aluminum. The said alloy, after casting into a sand mold, exhibits the following properties:

- tensile strength Rm = 330 MPa

- relative elongation A5 = 2.4%

- average value of the dry friction coefficient (counter-sample made of C45 50HRC steel) 0.32-0.34

- linear wear of the sample on the friction distance 10 km 0.6 mm

By comparison, an alloy that does not contain titanium has the following properties:

- tensile strength Rm = 325 MPa

- relative elongation A5 = 1.95%

- average value of the dry friction coefficient (counter-sample made of C45 50HRC steel) 0.32-0.34

- sample linear wear on the friction distance 10 km 0.8 mm

Claims (1)

1. A high-zinc aluminum alloy containing, by weight, 1.5-3.5% copper, 0.001-0.2% titanium, 0.2-1.5% manganese, and zinc, characterized by a 27.0- 45.0% zinc and 0.01-0.5% of at least one element selected from the group consisting of chromium, silicon, iron, magnesium, nickel with the rest being aluminum.