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采用机械合金化,随后在750℃、58MPa下热压制备了致密的块体纳米晶Cu60Ni20Cr20合金,用X射线衍射仪、扫描电子显微镜等分析手段对比研究了不同晶粒尺寸的Cu60Ni20Cr20合金的显微组织。结果表明:随着球磨时间的延长,由于晶粒的细化和应变的结果,衍射峰偏移并有明显的宽化产生,Cr在Cu中的固溶度明显增加,在球磨40h后,合金已由双相变成亚稳态的单相。由于机械合金化的粉末处于非平衡态,其过饱和固溶体随热压和真空退火过程的进行会慢慢分解,合金由单相变成两相,α Cu和γ Cr两相颗粒均成倍长大,但仍保持纳米级尺度。扫描电子显微镜(SEM/EDX)观察表明,合金致密度很高且显微组织均匀。讨论了晶粒细化对合金显微组织的影响。
The compact nanocrystalline Cu60Ni20Cr20 alloy was prepared by mechanical alloying followed by hot pressing at 750 ℃ and 58MPa. The microstructures of Cu60Ni20Cr20 alloy with different grain sizes were studied by means of X-ray diffraction and scanning electron microscopy. organization. The results show that as the ball milling time prolongs, the diffraction peak shifts due to grain refinement and strain, and the broadening occurs. The solid solubility of Cr in Cu increases obviously. After 40h milling, the alloy Has changed from biphasic to metastable single phase. Due to the mechanical alloying powder is in the non-equilibrium state, the supersaturated solid solution will slowly decompose with the hot pressing and vacuum annealing process, the alloy changes from single phase to two phases, α Cu and γ Cr two-phase particles are doubled Large, but still maintain nano-scale. Scanning electron microscopy (SEM / EDX) observations show that the alloy has high density and uniform microstructure. The effect of grain refinement on the microstructure of the alloy was discussed.