化学成分对GH4169合金组织与力学性能的影响

针对不同Nb、Al、Ti含量的GH4169合金,对其进行固溶时效热处理,研究微观组织与拉伸性能的变化规律。研究表明,一定的Al/Ti和(Al+Ti)/Nb值下,随Nb含量增加,δ相含量增加,并且具有较好的高温稳定性,高温固溶可有效阻止晶粒的长大,主要通过稳定的δ相来保证合金的细晶强化。当Al/Ti与(Al+Ti)/Nb比值较低时,时效后γ″、γ'含量有所降低,γ″相形貌由唇状变为圆盘或芝麻粒状,其中Nb元素主要形成δ相。力学性能表明,Al/Ti和(Al+Ti)/Nb值一定时,拉伸强度主要受晶粒尺寸影响,而δ相含量影响较小。但当Al/Ti与(Al+Ti)/Nb比值较低时,由于强化相γ″和γ'数量与形貌的变化,拉伸力学性能显著降低,其微观硬度也随拉伸强度的降低而降低。

Effect of chemical composition on microstructure and mechanical properties of GH4169 alloy

The microstructure and tensile properties of GH4169 alloy with different Nb, Al and Ti contents were studied after solution and aging treatment. The results show that under certain Al/Ti and (Al+Ti)/Nb ratios, the δ phase increases in amount with the increase of Nb content and has better high temperature stability; meanwhile, the high temperature solution treatment can effectively prevent grain growth and ensure the fine grain strengthening by the stable δ phase. When the Al/Ti and (Al+Ti)/Nb ratios are relatively low, the contents of γ″ and γ' phases decrease, and the morphology of γ″ changes from lip-shape to disc-shape or sesame-like shape, in this case the Nb element will mainly form δ phase. The results of mechanical properties show that when the Al/Ti and (Al+Ti)/Nb ratios are similar, the tensile strength is mainly affected by grain size, while the effect of δ phase content is less. However, when the Al/Ti and (Al+Ti)/Nb ratios are relatively low, due to the quantity and morphology changes of the strengthening phases γ″ and γ', the tensile properties are significantly poorer, and the microhardness also decreases along with the decrease of tensile strength.