CAJ | 학술논문

基于Thermo-Calc热力学模拟软件、扫描电镜和能谱仪等实验手段,研究GH625合金铸态试样棒的显微组织,并对比讨论浇注温度对其显微组织的影响规律. GH625合金的铸态显微组织为发达的树枝晶,枝晶间可见δ相与M6C型碳化物伴生析出. 一次枝晶臂间距λ1 和二次枝晶臂间距λ2 均随着浇注温度的升高而增大,而枝晶偏析程度则同时受扩散时间和扩散距离两方面因素的共同作用,综合相互作用导致1420℃浇注试样里Nb元素高度偏析,为枝晶间δ相的大量析出提供有利的浓度条件. 因此,在制定浇注工艺时,需要综合考虑扩散时间和扩散距离的影响程度,选取合适的浇注温度(或者冷却速率).
기우Thermo-Calc열역학모의연건、소묘전경화능보의등실험수단,연구GH625합금주태시양봉적현미조직,병대비토론요주온도대기현미조직적영향규률. GH625합금적주태현미조직위발체적수지정,지정간가견δ상여M6C형탄화물반생석출. 일차지정비간거λ1 화이차지정비간거λ2 균수착요주온도적승고이증대,이지정편석정도칙동시수확산시간화확산거리량방면인소적공동작용,종합상호작용도치1420℃요주시양리Nb원소고도편석,위지정간δ상적대량석출제공유리적농도조건. 인차,재제정요주공예시,수요종합고필확산시간화확산거리적영향정도,선취합괄적요주온도(혹자냉각속솔).
The microstructure of as-cast GH625 alloy was investigated on the basis of experimental methods such as Thermo-Calc software, scanning electron microscopy and energy dispersive spectroscopy. The effect of casting temperature on the microstructure was also analyzed by comparing different samples. The microstructure of as-cast GH625 alloy is a dendritic structure and M6C carbides accompanied with δ phase precipitate in the interdendritic area. Both primary dendrite arm spacing (λ1 ) and second dendrite arm spacing (λ2 ) increase with the increase of casting temperature; however, the microsegregation is affected by both diffusion distance and diffusion time. The comprehensive interaction of these two factors leads to the greatest microsegregation degree of Nb at 1420℃, which contributes to δ phase precipitation in the interdendritic area. As a result, diffusion distance and diffusion time should be comprehensively considered in making the casting process, so as to choose a proper casting temperature ( or cooling rate) .