Achieving High Strength and High Electrical Conductivity of Additive Manufactured CuCrZr Alloys: The Role of the Post-Heat Treatments on Microstructure and Properties

In this work, two different types of post-heat treatment processes were developed for additively manufactured CuCrZr alloy. The effect of post-heat treatment on the microstructure and properties of as-built CuCrZr alloy was studied in detail. After the direct aging of the as-built samples, the cellular substructure was preserved and a large number of fine Cu4Zr and Cr particles were precipitated in the matrix. However, after solid solution and age-hardening treatment, the grains in the sample coarsened to hundreds of microns and the annihilation of the cellular substructure occurred. Compared with the samples after solid solution and age-hardening treatment, the directly aged samples had an excellent combination of hardness (191 & PLUSMN; 7 HV), strength (513 & PLUSMN; 8 MPa) and electrical conductivity (82.2 & PLUSMN; 1.5 pct IACS). The high strength of the directly aged samples can be attributed to the enhancement of the strengthening mechanism of the precipitated particles and the retention of the cellular substructure. In addition, the reduction of solid solution atoms would significantly weaken the electron scattering effect, thereby improving the electrical conductivity.