铸态和T6热处理Al-Si-Cu-Ni-Ce-Cr铸造耐热铝合金的组织和力学性能

使用OM、SEM观察、XRD物相分析和拉伸性能测试等手段研究了铸态、固溶态和时效Al-Si-Cu-Ni-Ce-Cr铸造耐热铝合金的组织和力学性能。结果表明:对Al-Si-Cu-Ni-Ce-Cr合金进行490℃×2 h+520℃×2 h双步固溶处理,不仅使θ-Al2Cu相完全固溶进基体中,还使更多的γ-Al7Cu4Ni相和δ-Al3CuNi相充分固溶进基体中,实现了更好的固溶效果;经过490℃×2 h+520℃×2 h和185℃×6 h热处理后,Al-Si-Cu-Ni-Ce-Cr合金的室温抗拉强度为336.8 MPa、高温(300℃)抗拉强度为153.3 MPa,比铸态分别提高了74%和19.3%。

Microstructure and Mechanical Properties of as Cast and Heat-treated Al-Si-Cu-Ni-Ce-Cr

The microstructure and mechanical properties of Al-Si-Cu-Ni-Ce-Cr alloy after different heat treatment were investigated by optical microscope, scanning electron microscope, X-ray diffraction and universal tensile testing. Results show that the θ-Al₂Cu phase completely dissolved into the matrix and the γ-Al₇Cu₄Ni and most of the δ-Al₃CuNi phases dissolved into the matrix after two steps solution treatment. When the Al-Si-Cu-Ni-Ce-Cr alloy was treated by 490°C×2 h+520°C×2 h+185°C× 6 h, the ultimate tensile strength at room temperature and 300°C is 336.8 MPa and 153.3 MPa, respectively. Compare with the as-cast Al-Si-Cu-Ni-Ce-Cr alloy, the value of tensile strength at room temperature and 300°C increases 74% and 19.3%, respectively.