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采用液态金属冷却法在恒定温度梯度GL=334 K/cm,大生长速率范围内(2~300μm/s)对Ni-45.5Al-9Mo(摩尔分数,%)共晶合金进行定向凝固制备。研究生长速率(v)对纤维间距(λ)、纤维直径(d)和纤维体积分数的影响。在实验中发现平界面和胞界面两类共晶生长界面。在平界面和胞界面组织中,生长速率(v)与纤维间距(λ)和纤维直径(d)的关系经回归分析分别为:λv1/2=5.90μm·μm1/2·s1/2和dv1/2=2.18μm·μm1/2·s1/2。Mo纤维的体积分数可在一定的范围内随生长速率进行调整,这是由生长过程中界面前沿过冷度的增加及共晶组织中各组成相的生长特性引起的。
Ni-45.5Al-9Mo (mole fraction,%) eutectic alloy was prepared by liquid metal cooling method with constant temperature gradient of GL = 334 K / cm and large growth rate range of 2 ~ 300μm / s. The effects of growth rate (v) on fiber spacing (λ), fiber diameter (d) and fiber volume fraction were studied. In the experiment, two types of eutectic growth interfaces were found, that is, flat interface and cell interface. The relationship between growth rate (v) and fiber spacing (λ) and fiber diameter (d) in flat and interfacial tissues was analyzed by regression analysis: λv1 / 2 = 5.90μm · μm1 / 2 · s1 / 2 and dv1 /2=2.18μm·μm1/2·s1/2. The volume fraction of Mo fibers can be adjusted with the growth rate within a certain range, which is caused by the increase of the undercooling of the interface and the growth characteristics of the various phases in the eutectic structure during growth.