【作者】 高雪松； 黄因慧； 田宗军； 刘志东； 沈理达； 王桂峰；

【Author】 GAO Xue-song,HUANG Yin-hui,TIAN Zong-jun,LIU Zhi-dong,SHEN li-da,WANG Gui-feng(College of Mechanical and Electrical Engineering,Nanjing University of Aeronautics and Astronautics,Naijing 210016,China)

【机构】 南京航空航天大学机电学院；

【摘要】 在不同冷却温度DD3高温合金基体上利用激光烧结技术制备了定向凝固KGH95镍基高温合金试样,并利用扫描电子显微镜、XRD等设备,分析了试样的显微组织特征,并对试样的高温冲击韧性性能进行了测定。结果表明,在半导体冷却-20℃基底上成型的高温合金块体结构致密,枝晶沿着垂直于基底的方向生长,一次枝晶间距5μm。枝晶生长受到基体温度的影响。在常温下,枝晶生长受扫描方向影响;而在氮气超低温冷却的条件下,枝晶虽沿着与基底垂直的方向生长,但受超高过冷度影响,烧结块体孔洞明显。高温冲击韧性表明,烧结块体的性能受枝晶生长方向及均匀性影响。更多还原

【Abstract】 Directional solidification KGH95 superalloy samples were prepared on DD3 superalloy substrate at different cooling temperatures by laser sintering.The microstructure and the mechanism of the samples are analyzed with SEM and XRD,and high-temperature impact toughness properties were determined.The results show that the superalloy sample is dense on substrate at-20 ℃ by semiconductor refrigeration,dendrite growth along the direction perpendicular to the substrate,primary dendrite arm spacing of the rapidly solidified columnar grains was as low as 5μm.Dendrite growth is the impact of substrate temperature.At room temperature,Dendrite growth affected by the scanning direction;Dendrite growth along the direction perpendicular to the substrate at under the conditions of liquid nitrogen ultra-low temperature cooling,but sintered sample has obvious holes under the high undercooling effects.High-temperature impact toughness showed that the performance of sintered samples by the dendrite growth direction and uniformity effects.更多还原