Copper multicomponent alloy and its use

Abstract

The invention relates to a copper multicomponent alloy, consisting of [in % by weight]:

Description

EXAMPLE

In series of tests, ingots with different Mn—Si ratios were cast and then cold-worked further. The alloy variants tested are summarized in Table 1. The cast ingots were homogenized in the temperature range between 700 and 800° C. and then milled. Strips with thicknesses of between 2.5 and 2.85 mm were produced by a plurality of cold-forming stages and intermediate annealing steps. The strips were cold-rolled and annealed in the temperature range between 700 and 800° C. in order to achieve sufficient cold-formability.

TABLE 1
	Cu	Ni	Sn	Mn	Si
Cu −	[% by	[% by	[% by	[% by	[% by
Ni − Sn + Mn + Si	weight)	weight]	weight]	weight]	weight]
Variant 1	Remainder	5.6–6.0	5.2–5.6	1.7–2.0	0.2–0.3
Variant 2	Remainder	5.6–6.0	5.2–5.6	1.3–1.6	0.2–0.3
Variant 3	Remainder	5.6–6.0	5.2–5.6	1.3–1.6	0.5–0.7
Variant 4	Remainder	5.6–6.0	5.2–5.6	0.8–1.0	0.1–0.3
Variant 5	Remainder	5.6–6.0	5.2–5.6	0.8–1.0	0.3–0.5
Variant 6	Remainder	5.6–6.0	5.2–5.6	0.4–0.6	0.4–0.6
Variant 7	Remainder	5.6–6.0	5.2–5.6	0.9–1.1	0.9–1.1
Variant 8	Remainder	5.6–6.0	5.2–5.6	1.8–2.1	0.5–0.6
Variant 9	Remainder	5.6–6.0	5.2–5.6	1.8–2.1	0.9–1.1

As expected, it was confirmed that the cold-formability of the Cu—Ni—Sn alloy modified with silicides is slightly lower than in the case of a Cu—Ni—Sn alloy without further silicide phases.

In a further process step, strips of this type can be combined to form a strong material composite by roll-cladding processes. Silicide-modified Cu—Ni—Sn alloys also have a significantly lower coefficient of friction than the silicide-free variant. The alloy according to the invention is therefore particularly suitable as a primary material for use as a sliding element (liners, thrust washers, etc.) in the automotive industry for engines, transmissions and hydraulics.

FIG. 1 shows a scanning electron microscopy image of the surface of a copper multicomponent alloy. The relatively finely distributed manganese-nickel silicides 2, which are embedded in the alloy matrix 1, can be clearly seen. These silicides are formed as the first precipitation in the melt in a temperature range as early as around 1100° C. If the melt composition is selected appropriately, the available silicon and manganese are precipitated together with a nickel content which is present in excess to form the silicide. The nickel content consumed in the silicide can be suitably taken into account for the subsequent formation of the matrix by using a higher nickel content in the melt.

The composition of the silicides does not necessarily have to correspond to a predetermined stoichiometry. Depending on the procedure adopted, determined in particular by the cooling rate, ternary intermetallic phases precipitate in the form of the silicides of type (Mn, Ni)_xSi, which are in the range between the binary boundary phases Mn₅Si₃ and Ni₂Si.

The mechanical properties of strips of the silicide-containing copper multicomponent alloy, in the as-rolled state, had a tensile strength Rm of 560 MPa and a yield strength of 480 MPa with an elongation at break A5 of 25%. The hardness HB was approx. 176.

After age-hardening of the strips, a tensile strength Rm of 715 MPa and a yield strength Rp_0.2 of 630 MPa with an elongation at break A5 of 17% were determined. The hardness HB was approx. 235.

Claims

1. Copper multicomponent alloy, consisting of [in % by weight]:

2. Copper multicomponent alloy according to claim 1, characterized in that it contains up to 2.5% Mn and up to 1.5% Si.

3. Copper multicomponent alloy according to claim 2, characterized in that it contains up to 1.6% Mn and up to 0.7% Si.

4. Copper multicomponent alloy according to claim 1, characterized in that it has undergone at least one heat treatment at 300 to 500° C.

5. Copper multicomponent alloy according to claim 1, characterized in that it has undergone at least one heat treatment at 600 to 800° C.

6. Copper multicomponent alloy according to claim 1, characterized in that it has undergone a combination of at least one solution anneal at 600 to 800° C. and at least one age-hardening treatment at 300 to 500° C.

7. Use of the copper multicomponent alloy according to claim 1 for sliding elements or plug connectors.