US1960916A - Aluminium alloy - Google Patents

Description

Patented May 29, 1934 PATENT OFFICE 1,960,916 ALUMINIUM ALLOY Alfred John Murphy and Stanley Alfred Edward Wells, Teddington, England, assignors to J.

' Stone & Company Limited, Deptford, England,

a corporation of Great Britain i No Drawing. Application June 14, 1933, Serial No. 675,866. In Great Britain June 29, 1932 2 Claims.

This invention comprises improvements in aluminium alloys and in particular aluminium alloys of the class containing copper, nickel, magnesium, iron and silicon.

The object of the invention is to produce an alloy of this class having its grain refined, possessing improved running and casting qualities, having high mechanical strength capable of being' enhanced by appropriate heat treatment, and, without detriment to any of these characteristics, having a capacity for carrying a high iron content.

According to this invention, cerium is added to an aluminium alloy of the class referred to, the alloy thereby being cleansed and acquiring the properties referred to and being enabled to carry an iron content which is added to it in predetermined proportion and in accordance with the value of the cerium addition. The alloy has particularly advantageous casting qualities. It may be submitted to appropriate high and/or low temperature treatment, the final product being highly cleansed and possessing a refined grain and high mechanical strength. Certain micrographical constituents which make for structural weakness, are reduced by the addition of cerium, as compared with the results obtained when other metals are employed for a similar purpose. The approximate ranges of composition 01. the alloys in which we have discovered that these beneficial effects are exhibited are as follows:

According to one practical process in accordance with these improvements, an alloy is made up as Iollowsz-Ferro-aluminium, containing 10 per cent iron, is added to molten aluminium in the desired proportion. The following are then added in succession and in the proportions required to give the desired compositionz cerium-iron-aluminium alloy containing 5 per cent cerium, 10 per cent iron and 85 per cent aluminium; nickel-aluminium alloy containing 20 per cent nickel; copper-aluminium alloy containing 50 per cent copper; silicon-aluminium alloy containing 12 per cent silicon, and, finally magnesium. Alternatively, the cerium may be added as the pure metal, or as an alloy with any of the other components of the final alloy. The sequence of additions may also be altered from the above. a

The subsequent treatment for enhancing the mechanical properties of the alloys may be carried out by quenching or rapidly cooling them from a temperature of 480 C. to 570 C. followed by ageing at a temperature not exceeding 300 C. Thus the treatment may be carried out in two stages. The'first, for a period of four hours at 560 C. and the second for a period of sixteen hours at 200 C. These periods and temperatures have been found suitable for ordinary purposes but they may be varied so as to give other combinations of high and low temperatures and periods of treatment. Alternatively, the alloys may be aged at a temperature not exceeding 300 0. without previous treatment at higher temperatures after casting.

It will be understood that the cerium addition is the important consideration for the purpose described. In some alloys, manganese, chromium and titanium may be introduced in predetermined proportions as further additions but not as substitutes for the cerium.

It is desirable to increase the cerium content as the iron content is increased and the duration of the first heat treatment stage may be increased as the iron content is increased, the said period also varying,'of course, with the type of microstructure desired. I

Within the general limits above indicated some alloys are preferred for castings and others for forgings. This will be seen from the following examples:-

Remainder.

Another advantage obtained when using cerium, as compared with a metal such as titanium, is that the melting point is lower so that the making upof the alloy is facilitated.

We claim:-

1. An aluminium alloy containing 0.5 to 5.0 per cent copper, 0.5 to 3.0 per cent nickel, 0.1 to 2.5

per cent magnesium, 0.2 to 2.5 per cent silicon, 0.2 to 2.0 per cent iron, 0.02 to 1.0 per cent cerium, and the balance substantially all aluminium.

2. An aluminium alloy containing 0.5 to 5.0

mium and manganese for imparting the characteristics of resisting corrosion and increasing hardness, in the proportions of 0.02 to 0.20 per cent chromium and 0.1 to 0.5 per cent mangaper cent copper, 0.5 to 3.0 per cent nickel, 0.1 to nese, and the balance substantially all aluminium.

ALFRED JOHN MURPHY. STANLEY ALFRED EDWARD WELLS.