硼对快凝Ni_3Al组织结构及力学性能的影响

INFLUENCE OF BORON ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF RAPIDLY SOLIDIFIED Ni_3Al

本文通过快凝及加硼合金化的方法改善金属间化合物Ni_3Al的韧性。实验表明:加入0.5-1.4at.-%的硼对Ni_3Al的塑性提高最有利。结构分析表明:在含1.37at.-%硼的Ni_3Al中,硼以Ni_(23)B_6弥散相及晶界偏聚方式存在;当硼量增至2.22at.-%时,硼以粗大的Ni_(23)B_6及NiB_(12)相在晶界处析出。无硼的Ni_3Al晶界为大角度晶界;当硼加至1.37at.-%时,Ni_3Al晶界以位错排列成亚晶界,以小角晶界形式存在。

By means of nonstoichiometry, rapid solidification and adequate bo-ron addition, the tensile strength and bending resistance of Ni_3Al has been improved.When adding 0.52 to 1.37 at.-% B into Ni_3Al, which has the beneficial effect onthe ductility. If boron addition is too high, there are coarse Ni_(23)B_6 particles andNiB_(12) phases found on the grain boundaries. Boron modification in Ni_3Al promotesthe ordering in the region near grain boundaries. The grain boundary of boron freeNi_3Al is a large angle one, but turns into a small angle grain boundary with sub-grains of dislocation characteristics when the boron content in Ni_3Al reaches 1.37at.-%.