Monitoring the precipitation reactions in a cold-rolled Al–Mn–Mg–Cu alloy using thermoelectric power and electrical resistivity measurements
Monitoring the precipitation reactions in a cold-rolled Al–Mn–Mg–Cu alloy using thermoelectric power and electrical resistivity measurements
复制标题
DOI：
10.1080/01418610108216652
复制
发表时间：
2001-08
期刊：
影响因子：
--
通讯作者：
S. I. Vooijs;S. Davenport;I. Todd;S. Zwaag
中科院分区：
文献类型：
--
作者：
S. I. Vooijs;S. Davenport;I. Todd;S. Zwaag
本文的目的是监测普通铝合金AA 3104和富镁富铜合金3104在等温退火过程中的多重析出反应。特别强调了位错对析出动力学的影响，因此在退火处理之前采用了不同的冷轧变形量。使用温差电势(TEP)和电阻率测量，可以分离同时和顺序的沉淀反应，并减少关于实际发生的沉淀反应的不确定性。结果表明，无论预变形量大小，Al2CuMg析出物均在较低的温度下形成。在350℃及更高温度下的热处理过程中，唯一发生的过程是含锰弥散体的析出。这一析出过程的速率受热处理前冷加工程度的强烈影响。从TEP和电阻率联合实验中获得的定性信息得到了透射电子显微镜观察的支持。也可以半定量地计算出沉淀元素的重量分数。将这些计算的分数与平衡热力学数据进行了比较，结果表明，在400°C以下，Al2MgCu的析出和Mn的析出符合得很好。
Abstract The aim of the present paper is to monitor multiple precipitation reactions in a normal Al alloy AA 3104 and a Mg- and Cu-rich alloy 3104 during isothermal annealing. Special emphasis is placed on the influence of dislocations on the precipitation kinetics and therefore different cold-rolling reductions are applied prior to the annealing treatment. Using both thermoelectric power (TEP) and electrical resistivity measurements it is possible to split concurrent and sequential precipitation reactions and to reduce the uncertainty about the actual precipitation reactions taking place. It is found that Al2CuMg precipitates form at low annealing temperatures, irrespective of the extent of pre-deformation. During annealing at temperatures from 350°C and higher, precipitation of Mn-containing dispersoids is determined as the only process occurring. The rate of this precipitation process is strongly influenced by the degree of cold work prior to the heat treatment. The qualitative information derived from the combined TEP and electrical resistivity experiments is supported by transmission electron microscopy observations. It is also possible to calculate the weight fractions of the elements precipitated semiquantitatively. These calculated fractions are compared with equilibrium thermodynamic data and show good agreement for the precipitation of Al2MgCu and the precipitation of Mn at temperatures up to 400°C.