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研究了Nb含量对铸造高铝Ti Al合金高温强度和室温塑性的影响。结果表明,合金900℃的抗拉强度随Nb含量的增加先升高后降低,Nb含量在4%~9%(原子分数)之间的高铝合金表现出优异的高温强度水平,其中7%Nb合金最高,达587 MPa。分析认为,在高Nb合金化固溶强化的基础上,Al/Ti反位缺陷造成的强化效应、层片组织处于拉伸硬取向以及应变诱发的形变孪晶强化也有可能是高Nb含量高铝铸造Ti Al合金900℃具有优异强度水平的重要机制。合金室温塑性随Nb含量的增加而呈线性下降,由2%Nb合金的1.2%降为9%Nb合金的0.3%,这可能是由于B2相随Nb含量的增加而显著增加所致。
The effect of Nb content on the high temperature strength and room temperature plasticity of cast Al-TiAl alloy was investigated. The results show that the tensile strength of the alloy increases first and then decreases with the increase of Nb content, and the high aluminum alloy with Nb content between 4% and 9% (atomic fraction) shows excellent high temperature strength, in which 7% Nb alloy highest, up to 587 MPa. Based on the analysis of high-Nb alloying solid solution strengthening, the strengthening effect caused by Al / Ti anti-phase defects, the tensile hard orientation and strain-induced deformation twinning in the lamellar structure may also be the result of high Nb content Casting Ti Al alloy 900 ℃ has an important mechanism of excellent strength level. The room-temperature ductility decreases linearly with the increase of Nb content from 1.2% of 2% Nb alloy to 0.3% of 9% Nb alloy, which may be attributed to the significant increase of B2 phase with the increase of Nb content.