摘要:
Bulk Al/Al
3Zr composite was prepared by a combination of mechanical alloying (MA) and hot extrusion processes. Elemental Al and Zr powders were milled for up to 10 h and heat treated at 600℃ for 1 h to form stable Al
3Zr. The prepared Al
3Zr powder was then mixed with the pure Al powder to produce an Al-Al
3Zr composite. The composite powder was finally consolidated by hot extrusion at 550℃. The mechanical properties of consolidated samples were evaluated by hardness and tension tests at room and elevated temperatures. The results show that annealing of the 10-h-milled powder at 600℃ for 1 h led to the formation of a stable Al
3Zr phase. Differential scanning calorimetry (DSC) results confirmed that the formation of Al
3Zr began with the nucleation of a metastable phase, which subsequently transformed to the stable tetragonal Al
3Zr structure. The tension yield strength of the Al-10wt%Al
3Zr composite was determined to be 103 MPa, which is approximately twice that for pure Al (53 MPa). The yield stress of the Al/Al
3Zr composite at 300℃ is just 10% lower than that at room temperature, which demonstrates the strong potential for the prepared composite to be used in high-temperature structural applications.