Creep resistance of lead-copper alloys. Influence of different thermomechanical treatments

We have taken up again the study of creep in lead-copper alloys used for a long time as roofing. Three structural states were examined : sand cast, ro lled, rolled-rehomogenized. The tests were carried out at temperatures of 2 0, 80 and 110 degreesC and under stresses of 1 to 10 MPa. The sand cast and rolled-rehomogenized alloys have a better resistance to creep than the rol led alloy. The explanation rests in the difference of the size of the matri x grains and in the copper distribution.