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用自制的高能球磨机将Cu-Ti和Ni-Ti二元系的纯金属粉末混合物制成了非晶粉末,确定了用机械合金化制取非晶含金粉末的一般工艺条件。用X射线衍射(XRD)方法研究了机械合金化时的非晶化过程。通过高温XRD和热差分析(DTA)方法检测了非晶粉末的晶化行为。实验发现,球料比应加以限制,在我们的实验条件下10:1是较适当的,机械合金化过程可能保存的少量层状结晶相通过随后在低于晶化温度T_X下的加热可能转化成非晶相。Cu_(43)Ti_(57)非晶粉末的T_X约等于450℃,Ni_(45)Ti_(55)约等于500℃。计算了Cu-Ti二元系在300℃时亚稳相和平衡相的自由能曲线,并根据扩散偶的模型讨论和解释了机械合金化的非晶化过程。
Using a homemade high-energy ball mill, the pure metal powder mixture of Cu-Ti and Ni-Ti binary system was made into amorphous powder, and the general process conditions for preparing amorphous gold-containing powder by mechanical alloying were determined. The amorphization during mechanical alloying was investigated by X-ray diffraction (XRD). The crystallization behavior of amorphous powder was tested by high temperature XRD and thermal differential analysis (DTA). It has been found experimentally that the ball ratio should be limited to 10: 1 under our experimental conditions. The small amount of lamellar crystalline phase that may be retained by mechanical alloying may be converted by subsequent heating below the crystallization temperature T_X Into amorphous phase. The T_X of Cu_ (43) Ti_ (57) amorphous powder is about 450 ℃ and the value of Ni_ (45) Ti_ (55) is about 500 ℃. The free energy curves of metastable phase and equilibrium phase of Cu-Ti binary system at 300 ℃ are calculated. According to the model of diffusion couple, the amorphization process of mechanical alloying is discussed and explained.