Powder Forging and Mechanical Properties of Al Based Bulk Amorphous/Crystalline Hybrid Alloys

초록

Al based bulk hybrid alloys composed of amorphous Al-10Ni-6Ce(at%) matrix alloy and crystalline Al-8Fe-2Mo-2V-1Zr alloy(Vf=0.3) were fabricated by a powder forging process. The process involved pre-compaction of amorphous/crystalline powder mixtures by cold pressing and subsequent isothermal forging at temperatures from 250 to 450℃ with the strain rate of 10-2 s-1 to achieve the rod-shaped bulk hybrid alloys having 10 mm diameter. Similar process was used to obtain the same shaped bulk monolithic(Al-10Ni-6Ce) alloy to the hybrid alloy. The porosity decreased rapidly with increasing forging temperature up to 375℃ for both the monolithic and hybrid alloys. Fully dense bulk specimens with the porosity less than 1.5% were achieved when the forging was carried out at and above 375℃. Noticeably high compressive fracture strength of 1.2GPa with the compressive plastic strain of 1% was obtained at room temperature for the fully dense bulk hybrid specimen forged at 375℃. In contrast, the fully dense bulk monolithic specimen forged at 375℃ did not exhibit any compressive plastic strain although it possessed the very high compressive fracture strength of 1.4GPa.