摘要
真空感应熔炼时采用高纯氧化物坩埚及石墨坩埚,保持其他控制参数不变,得到名义成分为Ti-55.8%Ni的TiNi形状记忆合金铸锭,经完全相同的加工工艺制备成Φ1.5mm的TiNi合金丝材。用自制试验装置对所得TiNi合金丝材的室温低周弯曲疲劳性能进行评价。研究发现,使用氧化物坩埚熔炼所得材料的低周弯曲疲劳性能较使用石墨坩埚得到的材料有显著提高。杂质成分分析及SEM形貌观察显示合金中第二相夹杂物有所减少,这是其性能得到改善的主要原因。采用随机安排对比试验结果的t检验方法可以判断,氧化物坩埚使用中期所得到TiNi合金的疲劳性能较好。认为坩埚的连续使用次数过多坩埚材料性能的恶化是造成周期疲劳变坏的主要原因。
Ti-55.8%Ni ingot samples were obtained by vacuum induction melting in high-purity oxide crucible and graphite crucible, then followed by the same processes forging, rolling, rotary swaging and finally hot drawn to produce Φ 1.5 mm wires. Low cyclic bending fatigue （LCBF） behaviors of these TiNi wires were measured at room temperature. The results of this test showed that the fatigue life of materials obtained in oxide crucible （alloy L） was much longer than that obtained in graphite crucible （alloy G）. Chemical composition analyzed via ICP-AES and microstructure observed by SEM exhibited that in alloy L proportion of impurity and second phase were lower than those in alloy G, that might be the main reason for improvement of fatigue properties of TiNi wires. When one crucible was used continually for too many times, the number of cyclic failure of TiNi wires decreased obviously. That caused by oxide flake falling down from the oxide crucible or the crucible reacting with the melt alloy, as a result, oxide particles in ingots would increase.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2008年第2期252-256,共5页
Chinese Journal of Rare Metals
