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本文研究了钨在定向凝固高温合金中的重要作用,并据此研制了一个具有高比强度的实用定向凝固高温合金DZ17GW。该合金与不含钨,其它成分相同的DZ17合金相比,760℃,70.3kg/mm~2下的中温持久寿命提高2.5倍;.980℃,20.4kg/mm~2下的高温持久寿命提高近一倍。相份计算结果表明:在DZ17GW中加入3.8%的钨并不显著影响γ′相的总量,仅仅提高γ/γ′的点阵错配度,从而略微提高γ′相的强化作用。合金中的大部份钨进入γ基体,提高固溶体对位错运动的阻力,起到有效的固溶强化作用,从而显著提高合金的持久寿命。背应力计算结果进一步证明:DZ17GW合金持久性能的显著提高主要是由固溶体所引起的背应力的提高所致。
In this paper, the important role of tungsten in the directional solidification of superalloys has been studied, and a practical oriented solidification superalloy DZ17GW with high specific strength has been developed. Compared with the same DZ17 alloy without tungsten and other components, the alloy has a 2.5 times longer service life at medium temperature of 760 ° C and 70.3kg / mm 2, and has higher long-life at high temperature of .980 ° C and 20.4kg / mm ~ 2 Nearly doubled. The calculated results of phase fraction show that the addition of 3.8% tungsten in DZ17GW does not affect the total amount of γ ’phase, but only increases the mismatch of γ / γ’ and slightly enhances the strengthening effect of γ ’phase. Most of the alloy tungsten into the γ matrix, solid solution to improve the resistance to dislocation movement, play an effective role in solid solution strengthening, thereby significantly increasing the alloy’s long-life. The results of back stress further prove that the significant improvement of the lasting properties of DZ17GW alloy is mainly caused by the increase of the back stress caused by solid solution.