铸锭枝晶间距和冷变形量对Cu-15Ni-8Sn合金显微组织和硬度的影响

摘要

Cu-15Ni-8Sn alloy ingots with dendrite spacing of 11,18,23,50 mm,respectively,were prepared by intermediate frequency induction furnace and high frequency induction furnace,and then treated in the order of homogenization annealing,solid solution,cold deformation and aging.The effects of dendrite spacing of the ingot and cold deformation amount on the microstructure and hardness of the alloy were studied.The results show that the microstructures of the tested alloy ingots were obvious dendritic structures.After homogenization annealing and solid solution,the microstructure of the alloy with relatively small ingot dendrite spacing was relatively uniform. The deformation of grains in the alloy was relatively large with a relatively large cold deformation amount, furthermore the black discontinuous precipitates and the aging hardness peak appeared earlier after aging at 400 ℃. With the same cold deformation amount,the black discontinuous precipitates and the aging hardness peak appeared later in the alloy with relatively small ingot dendrite spacing.%采用中频感应炉与高频感应炉制备了枝晶间距分别为11,18,23,50μm的Cu-15Ni-8 Sn合金铸锭,并依次进行了均匀化退火处理、固溶处理、冷变形和时效处理,研究了铸锭枝晶间距和冷变形量对合金显微组织和硬度的影响.结果表明:试验合金铸锭的显微组织均为明显的树枝状组织;经均匀化退火及固溶处理后,铸锭枝晶间距越小的合金组织也越趋于均匀;冷变形量越大,合金中的晶粒变形越严重,且经400℃时效后合金中的黑色不连续脱溶产物越早析出,时效硬度峰也越早出现;在相同的冷变形量下,铸锭枝晶间距越小的合金中黑色不连续脱溶产物越晚析出,且时效硬度峰越晚出现.