In this paper, we have explored the availability of toughening of zirconium to Ni_3Al based alloys, it was confirmed that the ductility of polycrystalline Ni_3Al -based alloy increased significantly by adding suitable amount of zirconium, further more, the polycrystalline Ni_3Al-based alloys with a appropriate zirconium content can be cold rolled to a plate with the thickness about 2mm, and its ductility was comparable to that of alloys doped with boron. The toughening nature of zirconium (with a convenient contents) is not only confined to the Ni-riched Ni_3Al-based alloys, it is even effective to the slight Al-riched Ni_3Al based allosy, and adding zirconium properly can also improve the ductility from 600 ℃ to 800 ℃. In Ni_3Al-based alloys, zirconium slightly segregates to grain boundary examined by AES, and boron segregates to grain boundary. Therefore the effects of zirconium on ductility of Ni_3Al alloy is different from that of boron. The effects of Hf which have the similar nature of zirconium on ductility of Ni_3Al-based alloys is much lower than that of zirconium. The decrease of aluminium content in Ni_3Al-based alloys can improve its strength at room temperature and ductility. But with the decrease of aluminium contents in alloys, the strength appears a run down tendency. Adding zirconium together with titanium in Ni_3Al-based alloy can sharply increase its strength.
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