中文摘要：

采用真空非自耗＋真空白耗电弧熔炼的方法制备了Nb—Cr系多元合金的母合金锭；对母合金进行了1450℃，24h＋1000℃，24h的热处理：采用三点弯曲方法测试了合金的室温断裂韧性；进行了950℃不同时间的氧化实验。发现热处理后Nbss基体由树枝晶转变为等轴晶，而Laves相Cr2（Nb，Ti，Hf）则由块状转变为边界圆润的棒状；合金的室温断裂机制由电弧熔炼态的解理断裂转变为热处理后的准解理断裂：950℃的氧化产物为CrNbO4、HfO2、TiO2、CrNb11O29和Ti2Nb10O29。

英文摘要：

A master alloy ingot of Nb-Cr based multi-element alloy has been prepared by vacuum non-consumable arc-melting, and then vacuum consumable arc-melting and heat treated at 1450 ~C for 24 h and 1000 ℃ for 24 h, then oxidized at 950 ℃ in air for different times for the heat treated samples. The room temperature fracture toughness is measured by a three-point bending method. It has been found that the Nb based solid solution （Nbss） transforms from dendrites into equiaxed grains, and the Cr2（Nb,Ti,Hf） Leves phase transforms from blocks into rods with more smooth boundaries after heat treatment. The arc-melted samples rupture in a brittle cleavage mode, but the heat treated samples rupture in a quasi-cleavage mode. The scale is composed of CrNbO4, HfO2, TiO2, CrNb11O29 and Ti2Nb10O29 phases when the samples are oxidized at 950 ℃ for different times.