Oxidation of An Aluminum‐3 Per Cent Magnesium Alloy in the Temperature Range 200°–550°C
Oxidation of An Aluminum‐3 Per Cent Magnesium Alloy in the Temperature Range 200°–550°C
复制标题
200°–550°C 温度范围内 3% 铝镁合金的氧化
DOI：
10.1149/1.2428764
复制
发表时间：
1958
期刊：
影响因子：
--
通讯作者：
W. Smeltzer
中科院分区：
文献类型：
--
作者：
W. Smeltzer
对 3% 铝镁合金的氧化和镁蒸发动力学进行了研究。包括对所产生的表面氧化膜进行金相检查。该合金的抗氧化性可达200~350°C，在温度高于350°C时，氧化速率最初与氧化膜厚度成反比，在长时间暴露下转变为恒定速率。镁的选择性氧化导致在表面氧化物中形成铝夹杂物。这些夹杂物使合金表面呈现黑色。经过诱导期后，镁在高于 350°C 的温度下从合金中蒸发，诱导期的持续时间取决于温度。镁蒸发速率和合金氧化速率的比较表明，氧化膜具有抗金属氧化的能力。 先前的研究表明，含镁量高达 10% 的合金上的氧化膜结构取决于加热方式，室温下形成的非晶氧化物达到的最终温度可能会结晶为 v-氧化铝或 MgAl~O 和 MgO (i, 2)。如果这些合金暴露在蒸汽中，就会迅速形成氧化镁 (3-6)。 AI-Mg 合金的表面因高温氧化而变色为灰色至黑色，有人认为这种效应与氧化膜中的 MgO 含量有关 (2)。通过将 NaBF~ 挥发到氧化气氛中 (7)、将合金预先暴露于 HF (3) 或向金属中添加少量 Be (5, 8)，可以减少这种变色。尽管 Al 形成高度抗氧化的氧化膜 (9, i0)，但 Al 的添加会增加 Mg 的氧化速率 (ii, 12)。对于相反的情况，即向 Al 中添加 Mg，目前还没有相关信息。因此，在本研究中，研究了 A1-3% Mg 合金在纯氧中的氧化速率。还包括有关合金中镁蒸发速率和氧化膜金相检查的一些研究结果。
A study of the oxldation and magnesium evaporation kinetics has been carried out on an aluminum-3% magnesium alloy. A metallographic examination of the surface oxide films produced was included. The alloy was oxidation resistant to 200~ At temperatures greater than 350~ the oxidation rate was initially inversely proportional to the oxide film thickness, transforming to a constant rate for long exposures. Selective oxidation of magnesium caused formation of aluminum inclusions in the surface oxide. These inclusions imparted a black discoloration to the alloy surface. Magnesium evaporated from the alloy in a vacuum at temperatures greater than 350~ after an induction period, the duration of which was dependent on the temperature. A comparison of the magnesium evaporation and alloy oxidation rates demonstrated that the oxide film offered resistance to oxidation of the metal.It has been shown in previous investigations that oxide film structures on alloys containing up to 10% Mg are dependent on the mode of heating, and final temperatures attained as amorphous oxide formed at room temperature may crystallize into v-alumina or MgAl~ O, and MgO (i, 2). Magnesia forms rapidly on these alloys if they are exposed to steam (3-6). The surface of the AI-Mg alloy is discolored gray to black by high temperature oxidation and it has been suggested that this effect is associated with the MgO content of the oxide film (2). This discoloration is decreased by volatilization of NaBF~ into the oxidizing atmosphere(7), pre-exposure of the alloy to HF (3), or small additions of Be to the metal (5, 8). Although Al forms an oxide film highly resistant to oxidation (9, i0), Al additions increase the oxldation rates of Mg (ii, 12). For the converse case, additions of Mg to Al, information is not available. Hence, in this investigation the oxidation rates of an A1-3% Mg alloy in pure oxygen have been investigated. Some results of studies on Mg evaporation rates from the alloy and metallographic examination of the oxide films are also included.