Abstract

The ternary Ni–Al–AE phase diagrams, where AEs are the main alloying elements of high-temperature cast (γ' + γ) γ'-Ni₃Al-based alloys, are analyzed. Principal differences between the solidification schemes in the vicinity of the γ'-Ni₃Al and β-NiAl phases and the differences in the characters of the influence of the main AEs at their contents to 10 at % on the phase composition and the structure of multicomponent γ'-Ni₃Al-based VKNA-1V, VKNA-25, VKNA-4U, and IM730 alloys are detcted. The structural base of all the alloys are (γ' + γ) dendrites. In the first-type cobalt-free VKNA1V alloys, as well as in IC221M, IC218, IC438, and IC6SX alloys, coarse single-phase γ'-Ni₃Al precipitates, which are the degenerate eutectic L\( \rightleftarrows \) (γ' + γ) + γ', form in the interdendritic space. In the second-type cobalt-containing alloys at the same (~17 at %) aluminum content (VKNA-4U, VKNA-25) or in the chromium-containing cobalt-free alloys with an increased (~21 at %) aluminum content (IM730), the following two-phase precipitates form: the nonequilibrium β-NiAl phase, which represents the degenerate L\( \rightleftarrows \) (γ' + β) + β eutectic, forms inside γ'-Ni₃Al. The following solid-phase transformations are found to develop intensely in the second-type alloys on heating in the temperature range 1200–1300°C: the dissolution of the β-phase precipitates in the primary γ'-Ni₃Al precipitates, the dissolution or a weakening of the interdendritic γ'-phase precipitates, and a change in the morphology and orientations of the γ-phase precipitates in dendrites and the interdendritic space.

中文翻译：

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含铬，钼，钨，R和钴的Ni 3 Al–Ni–NiAlAl合金的凝固及其相态

摘要

三元镍-铝-AE相图，其中的AE是高温铸件的主要合金元素（γ” +γ）-γ'的Ni ₃ Al基合金，进行了分析。在γ'-Ni的附近的凝固方案之间的差异主要₃ Al和β-NiAl金属阶段和在它们的内容10的主要不良事件的影响的字符原子％的相组合物中的差异和结构多组分γ'-的Ni ₃ Al基VKNA-1V，VKNA-25，VKNA-4U，和IM730合金detcted。所有合金的结构基础都是（γ'+γ）树突。在第一类型的无钴VKNA1V合金，以及在IC221M，IC218，IC438和IC6SX合金，粗单相γ'-Ni系₃的Al的析出物，\（\ rightleftarrows \）（γ'+γ）+γ'，形成在树突间空间中。在铝含量相同（〜17 at％）的第二种含钴合金中（VKNA-4U，VKNA-25）或铝含量增加（〜21 at％）的含铬无钴合金中（IM730），下面的两个相沉淀物形成：非平衡β-NiAl金属相，其代表简并大号\（\ rightleftarrows \）（γ” +β）+β共晶，γ'-Ni系内部形式₃的Al。以下固相转变被发现强烈在所述第二类型的合金开发上的温度范围1200-1300℃下加热： -镍γ'β相析出物的溶解在初级₃Al析出，树枝状的γ'相析出物溶解或变弱，并且树枝状和枝晶间的间隙中的γ相析出物的形态和取向发生变化。