( 1. 中國科學(xué)院金屬研究所 金屬腐蝕與防護(hù)國家重點(diǎn)實(shí)驗(yàn)室，
沈陽 110016;
2. 沈陽師范大學(xué) 化學(xué)系， 沈陽 110034)
摘 要: 采用機(jī)械合金化， 隨后在750℃、 58MPa下熱壓制備了致密的塊體納米晶Cu60Ni20Cr20合金， 用X射線衍射儀、 掃描電子顯微鏡等分析手段對比研究了不同晶粒尺寸的Cu60Ni20Cr20合金的顯微組織。結(jié)果表明： 隨著球磨時(shí)間的延長， 由于晶粒的細(xì)化和應(yīng)變的結(jié)果， 衍射峰偏移并有明顯的寬化產(chǎn)生， Cr在Cu中的固溶度明顯增加， 在球磨40h后， 合金已由雙相變成亞穩(wěn)態(tài)的單相。由于機(jī)械合金化的粉末處于非平衡態(tài)， 其過飽和固溶體隨熱壓和真空退火過程的進(jìn)行會慢慢分解， 合金由單相變成兩相， α-Cu和γ-Cr兩相顆粒均成倍長大， 但仍保持納米級尺度。 掃描電子顯微鏡(SEM/EDX)觀察表明， 合金致密度很高且顯微組織均勻。 討論了晶粒細(xì)化對合金顯微組織的影響。
關(guān)鍵字: Cu60Ni20Cr20合金; 機(jī)械合金化； 晶粒尺寸； 顯微組織
（ 1. State Key Laboratory for Corrosion and Protection, Institute of Metal Research,
Chinese Academy of Sciences, Shenyang 110016, China;
2. Department of Chemistry, Shenyang Normal University, Shenyang 110034, China）
Abstract: The Cu60Ni20Cr20 bulk alloys have been prepared respectively by arc-melting and hot pressing the mechanically alloyed powders at 750℃ under a normal pressure 58MPa with much different grain sizes. Their micro-structural characteristics were investigated by X-ray diffraction(XRD), scanning electron microscopy(SEM) and energy-dispersive X-ray microanalysis(EDX). The results show that with the increase of ball milling time, the X-ray diffraction peaks have a deviation and broadening because of fine grain size and internal stress and the solid solubility of Cr in Cu increases evidently. When the powders were milled for 40h, the alloyed powders have become single solid solution. Because mechanically alloyed powders are in non-equilibrium state, the solvent in a state with certain degree of super-saturation can decompose slowly, finally the alloys have become double-phase from single phase solid solution. The sizes of α-Cu and γ-Cr phase particles increased but still remained nano-size after hot pressing and annealing in vacuum. The alloy possessed excellent density and showed little oxidation by SEM/EDX analysis. The effect of grain size on alloys microstructue was discussed in detail.
Key words: Cu60Ni20Cr20 alloy; mechanical alloying; grain size; microstructure
