【摘要】 利用透射电镜研究了Cu Ni Si合金 4 5 0℃时效的组织转变规律。结果表明 ,时效时过饱和固溶体首先发生成分调幅形成贫、富溶质区 ,之后在溶质富集区通过形核、长大产生与基体保持半共格的Ni2 Si相。时效 4h后 ,Ni2 Si相与基体的半共格关系破坏 ,合金硬度显著下降。利用位错理论计算与铜基体保持半共格界面的Ni2 Si相临界尺寸为r=6nm ,与实测数据非常吻合。更多还原

【Abstract】 The mechanism of microstructural transformation of Cu 3 2Ni 0.75 Si(mass fraction)aged at 450℃ has been studied by TEM.It is found that the supersaturated Cu Ni Si alloy solid solution first decomposes into rich solute and depleted solute regions by spinodal mechanism. Thereafter,the rich solute region undergoes nucleation and growth transformation to form a Ni\-2Si which remained semi\|coherent with the matrix.After aged for 4h,semi coherency was broken,while as the hardness of the alloy decreased distinctly.The critical size ( r ) of Ni\-2Si phase in semi coherent with matrix is calculated to be about 6nm in terms of the dislocation theory,which is quite consistent with the experiment data.更多还原