Analysis of the Influence of Sulfur on the Hot Tensile Fracture of C71500 Cu-Ni Alloy

摘要

The hot tensile test was applied to study the influence of sulfur content on the high-temperature mechanical properties of C71500 Cu-Ni alloy. The hot processing map of C71500 alloy was established according to the test results. It is found that the increase of sulfur content has no visible effect on the tensile strength of C71500 alloy at high temperature, but has a great effect on the elongation and reduction area of fracture. Through optical microscopy, scanning electron microscopy and energy-dispersive x-ray spectroscopy analysis of fracture samples, it can be qualitatively determined that the composition of sulfur inclusions is (Mn,Fe,Ni)S, which is plastically deformable in the process of hot deformation. However, due to the difference of plasticity between the inclusions and the matrix, stress concentration is easy to occur, thus reducing the overall plasticity of C71500 alloy. Based on the proposed dynamic material model theory, the processing maps with different sulfur contents were established, which could show the destruction effect of sulfur on the high-temperature plastic deformation of C71500 alloy.