在单晶高温合金的凝固过程中，难熔元素( 主要是 W 和Re) 往往偏析

During the solidification of the single crystal superalloy, refractory elements (mainly W and Re) tends to segregate in dendrite region, while the other γ 'phase forming elements (Al, Ti, and Ta) are often segregated in interdendritic regions , is formed in the final period of solidification and crystallization between branches <br><br>effluent (primary γ 'phase + γ / γ' eutectic), i.e., the cast single crystal superalloy exist <br><br>in the tissue and inhomogeneous composition. Therefore, to obtain a homogeneous microstructure in <br><br>organization and chemical composition of the cast single crystal superalloy require solution treatment, i.e., <br><br>the purpose of the solution treatment is to eliminate (or lessen) significantly interdendritic precipitates of Elements <br><br>micro segregation . Meanwhile, it is worth noting that, in order to ensure single crystal superalloy having <br><br>higher mechanical properties, the alloy generally require secondary γ 'phase is a cubic shape, <br><br>and a size of about 0.4 ~ 0.5 μm, and casting secondary state single crystal superalloy of <br><br>γ 'phase is generally irregular in shape, and sizes. Accordingly solution treatment improved <br><br>while organizing and composition uniformity, the need to ensure the secondary γ 'phase is wholly re-dissolution, i.e., <br><br>the solution temperature should be in the "heat treatment window"

In the solidification of single-crystal high-temperature alloys, refractory elements (mainly W and Re) tend to be partial to the branch stem area, while other gamma's formation elements (Al, Ti and Ta) tend to be partially analyzed in the intercrystalline region and form intercrystalline analysis at the end of the solidification<br><br>The excretion (the nassomal 'phase-and-s/'cocrystalline tissue) is stored in the cast-state single-crystal high-temperature alloy<br><br>In the tissue and composition of the unevenness. Therefore, in order to obtain a uniform microgroup<br><br>Weaving and chemical compositions, cast single-crystal high-temperature alloys require solid solution treatment, i.e.<br><br>The purpose of the solid-soluble treatment is to eliminate (or reduce) the manifestation of the intercrystalline precipitates and elements<br><br>Micro-bias. At the same time, it is worth noting that in order to ensure a single crystal high temperature alloy<br><br>Has a high mechanical properties, generally requires that the alloy's secondary gamma's phase is cubic,<br><br>And the size is about 0. 4 to 0. 5 sm, while secondary in cast single-crystal high-temperature alloy<br><br>The 'phase' is generally irregularly shaped and of different sizes. So the solid-soluble treatment is improved<br><br>While the degree of organization and composition uniformity, it is necessary to ensure that the secondary 'phase' is all back-soluble, i.e.<br><br>The solid temperature should be in the "heat treatment window"

In the solidification process of single crystal superalloys, refractory elements (mainly W and re) tend to segregate in the dendrite dry region, while other γ 'phase forming elements (al, Ti and TA) tend to segregate in the dendrite intercrystalline region, and form the dendrite intercrystalline segregation at the end of solidification<br>The product (primary γ 'phase + γ / γ' eutectic structure), i.e. existing in as cast single crystal superalloy<br>In the inhomogeneity of tissue and composition. Therefore, in order to obtain uniform microstructure<br>Texture and chemical composition, as cast single crystal superalloys need to be solution treated, i.e<br>The purpose of solution treatment is to eliminate (or reduce) the appearance of precipitates and elements between dendrites<br>Microsegregation. At the same time, it should be noted that in order to ensure the high temperature of single crystal alloy fittings<br>It has high mechanical properties, and generally requires the secondary γ 'phase in the alloy to be cubic,<br>And the size is about 0.4-0.5 μ m, but the second time in as cast single crystal superalloy<br>Generally, the shape of γ 'phase is irregular and its size is different. So solution treatment is improving<br>At the same time of the uniformity of the structure and composition, it is necessary to ensure that all the secondary γ 'phases are dissolved back, i.e<br>Solution temperature should be in "heat treatment window"