Rodak Kinga, Kuc Dariusz, Mikuszewski Tomasz
Faculty of Materials Engineering, Silesian University of Technology, Krasińskiego 8, 40-019 Katowice, Poland.
Materials (Basel). 2020 Dec 18;13(24):5803. doi: 10.3390/ma13245803.
The binary as-cast Al-Cu alloys Al-5%Cu, Al-25%Cu, and Al-33%Cu (in wt %), composed of the intermetallic θ-AlCu and α-Al phases, were prepared from pure components and were subsequently severely plastically deformed by extrusion combined with reversible torsion (KoBo) to refinement of α-Al and AlCu phases. The extrusion combined with reversible torsion was carried out using extrusion coefficients of λ = 30 and λ = 98. KoBo applied to the Al-Cu alloys with different initial structures (differences in fraction and phase size) allowed us to obtain for alloys (Al-25%Cu and Al-33%Cu), with higher value of intermetallic phase, large elongations in the range of 830-1100% after tensile tests at the temperature of 400 °C with the strain rate of 10 s. The value of elongation depended on extrusion coefficient and increase, with λ increasing as a result of α-Al and AlCu phase refinement to about 200-400 nm. Deformation at the temperature of 300 °C, independently of the extrusion coefficient (λ), did not ensure superplastic properties of the analyzed alloys. A microstructural study showed that the mechanism of grain boundary sliding was responsible for superplastic deformation.
由金属间化合物θ-AlCu和α-Al相组成的铸态二元Al-Cu合金Al-5%Cu、Al-25%Cu和Al-33%（重量百分比），由纯组分制备而成，随后通过挤压结合可逆扭转（KoBo）进行严重塑性变形，以细化α-Al和AlCu相。挤压结合可逆扭转是使用挤压系数λ = 30和λ = 98进行的。将KoBo应用于具有不同初始结构（金属间相分数和相尺寸的差异）的Al-Cu合金，使我们能够获得金属间相含量较高的合金（Al-25%Cu和Al-33%Cu），在400℃温度下以10 s的应变速率进行拉伸试验后，伸长率在830 - 1100%范围内。伸长率的值取决于挤压系数，并随着α-Al和AlCu相细化至约200 - 400 nm，λ增加而增大。在300℃温度下的变形，与挤压系数（λ）无关，不能确保所分析合金的超塑性性能。微观结构研究表明，晶界滑动机制是超塑性变形的原因。
