With the help of high temperature-gradient directional solidification equipment (HGDS), the microstructure and microsegregation of Ni-base single crystal superalloy CMSX-2 solidified at the cooling rates from below 1 K/s to 20 K/s were investigated.
实验发现采用高梯度定向凝固技术可以得到具有超细枝晶组织的单晶高温合金材料,枝晶偏析在低速生长时随冷却速率的增加而增加,而在高速生长时形成的超细枝晶组织中,枝晶偏析随冷却速率的增加而减小。
The dendritic arm spacings and microsegregations of directionally solidified superalloy DZ22 at various solidification rates have been studied with the help of a ZMLMC directional solidification equipment.
采用新研制的超高梯度定向凝固装置,研究了不同凝固速率下定向凝固高温合金DZ22的枝晶臂间距和枝晶偏析。
The results show that FGH95 alloy ingot exists serious dendrite segregation,dendrite segregation is eliminated when microstructure and composition are homogenized after 1170 ℃×20h or isothermal compression of 70% at 1150 ℃.
结果表明:FGH95合金铸锭存在严重的枝晶偏析,经1170℃×20h均匀化处理或在1150℃等温压缩70%后,合金铸锭的组织和成分达到均匀化,铸锭内的枝晶偏析得以消除,并且1150℃等温压缩70%工艺比1170℃×20h工艺所得的组织更加细小,晶粒平均尺寸约为85。
In view of generality and importance of effects of dendrite segregation on structures and properties of casted alloy materials, accurate mathematical models of diffusion homogenization of dendrite segregation must be set up,thus parameters of physico-metallurgical quality control can be found.
鉴于枝晶偏析对熔铸材料组织和性能影响的普遍性与重要性,需要建立准确的枝晶偏析扩散均匀化数学模型,以便找出冶金质量控制参数。
The results show that there were dendrite segregation,shrinkage and non-normal coarse bainite microstructure defects in the workpiece,which indicated that the metallurgical quality of the raw materials of the gear shaft was poor and these defects still had not been eliminated after forging.
结果表明:工件内部存在枝晶偏析、类孔隙性缩松等缺陷和非正常粗大的贝氏体网状组织,说明该齿轮轴原材料冶金质量差,虽然经过锻造但仍没有被消除,同时非正常组织的存在导致材料组织不均匀性进一步加大,这些都会大大恶化钢材的工艺性能和机械性能,结合裂纹形态可以认为该齿轮轴裂纹的产生主要由原材料缺陷等因素造成。
The results show that the addition of micro rare earth elements to low alloy tool steel can decreases relative content of gross carbide, improve the dispersion, refine the austenite grain and reduce the dendritic segregation of chromium.
结果表明:微量稀土的加入,可减少粗大碳化物的相对量,改善其分布状况,细化奥氏体晶粒,减少铬的枝晶偏析。
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