【作者】 王学双；

【导师】 魏尊杰；

【作者基本信息】 哈尔滨工业大学 ， 材料加工工程， 2011， 硕士

【摘要】 本论文以Ti-6Al-3Sn-3.6Zr-0.5Mo-0.45Si为主要的合金成分,向其成分中添加了0wt.%、1.5wt.%、3.0wt.%、4.5wt.%、6.0wt.%的Ta元素和0wt.%、0.5wt.%、1.0wt.%、1.5wt.%的Nb元素。分析了Ta元素和Nb元素以及热处理的工艺参数(温度:950℃、1020℃、1050℃;时间:30min、45min、60min)对合金组织、元素分布情况以及力学性能的影响。Ta元素和Nb元素加入后,XRD和能谱的分析表明,合金中含有α相和β相,并没有产生新相,Ta元素和Nb元素固溶在合金基体内,起到了固溶增强的作用。随着Ta元素和Nb元素含量的增加,铸态合金组织中的β相含量增加,α片层变厚;当复合添加Ta元素的质量分数为3.0wt.%,Nb元素的质量分数为1.0wt.%时,合金的组织为网篮组织,室温压缩性能出现峰值,抗压强度为1772.93MPa,屈服强度为1068.34MPa,压缩率为36.38%;比未加入Ta和Nb两种元素的合金,抗压强度提高了164.40MPa,屈服强度提高了118.12MPa,压缩率提高了6.49%。热处理过程中,合金内出现Mo、Nb、Ta这3个元素在α相和转变β相中偏聚的现象,温度越高、时间越长,3种元素在转变β相中的含量越多;随着Ta元素和Nb元素质量分数的增加,转变β相含量所占比例增大。当Ta元素和Nb元素的复合添加量分别为3.0wt.%和1.0wt.%,热处理温度和时间分别为1020℃和45min时,室温压缩性能出现峰值,抗压强度为1879.51MPa,屈服强度为1127.17MPa,压缩率为38.46%;比相同条件下,未加入Ta和Nb两种元素的合金,抗压强度提高了370.09MPa,屈服强度提高了131.80MPa,压缩率提高了7.23%;对合金的断口形貌分析表明,合金的断口上含有大量韧窝,因此塑性很好,为韧性断裂。更多还原

【Abstract】 The alloy was added Ta of 0wt.%, 1.5wt.%, 3.0wt.%, 4.5wt.%, 6.0wt.% and Nb of 0wt.%, 0.5wt.%, 1.0wt.%, 1.5wt.%, the main ingredient of which included Ti-6Al-3Sn-3.6Zr-0.5Mo-0.45Si. The effect of Ta, Nb and heat treatment (temperature:950℃,1020℃,1050℃;time:30min,45min,60min)on the microstructure, elements distributing and mechanical properties was analysised in the study.The analysis of XRD and EDS showed that the alloy containedαanbβphase after added Ta and Nb, but no new phase, then Ta and Nb dissolved in the alloy very well. The enhanced properties can be attributed to the solid-solution effects of Ta and Nb.Along with the increasing of Ta and Nb, the content ofβwas increased,αlamellar was thicker. As the mass fraction of Ta was 3.0wt.%, and Nb was 1.0wt.%, the microstructure of the alloy was basket microstructure at as-cast. The mechanical properties was the best: the compressive stress reached 1772.93MPa, the compressive yield stress was up to 1068.34MPa, the compressive rate of the alloy was 36.38%. Comparing with the alloy which didn’t contain Ta or Nb, the compressive stress was increased by 164.40MPa, the compressive yield stress was increased by 118.12MPa, the compressive rate was increased by 6.49%.In the process of heat treatment, Mo, Nb and Ta was unequal inαandβphase, the contents of the three elements were increased in the transformedβphase along with the tempreture and time increasing. After heat treatment, with the Ta and Nb increasing, the transformedβwas much more than before.When the addition of Ta and Nb was 3.0wt.% and 1.0wt.%, the temperature and time was 1020℃and 45 min, the compressive stress and the compressive yield stress was up to 1879.51MPa and 1127.17MPa, the compressive rate reached to 38.46%, which is the best performance of the heat treatment state. Comparing with the alloy which didn’t contain Ta or Nb under the same condition of heat treatment, the compressive stress was increased by 370.09MPa, the compressive yield stress was increased by 131.80MPa, the compressive rate was increased by 7.23%. The fracture surface was studied, which contained a large number of toughening nests, the plasticity was better.更多还原