摘要
The combined effects of equal channel angular pressing (ECAP) and subsequent heating to a semi-solid temperature on the microstructural characteristics of the 7075 aluminum alloy were investigated. The microstructure is influenced by several parameters including the number of ECAP passes, ECAP route, consequent heating temperature, and holding time. The effects of these parameters on the microstructural characteristics including grain size and shape factor of the 7075 aluminum alloy were studied using experimental tests and Taguchi method. The results indicate that five-pass ECAP in route BA and subsequent isothermal holding at 630 °C for 15 min are more appropriate for achieving a semi-solid microstructure. The processing route and holding time have the highest impact on the grain size while the number of ECAP passes and heating temperature have the least impact on the grain size. Meanwhile, the shape factor is significantly influenced by the processing route, holding time and heating temperature while it is less influenced by the number of ECAP passes.
研究等通道转角挤压(ECAP)及后续加热到半固态温度对7075铝合金显微组织的影响。7075铝合金的显微组织受ECAP道次、ECAP路径、后续加热温度和保温时间等参数的影响。采用实验及Taguchi法探讨上述参数对7075铝合金的微观特性包括晶粒尺寸及形状因子的影响。结果表明:5道次ECAP、路径BA及后续630°C等温处理15 min是合金获得半固态显微组织的较佳工艺条件;加工路径和保温时间对晶粒尺寸的影响最大,而ECAP道次和加热温度对晶粒尺寸的影响最小。形状因子受加工路径、保温时间和加热温度的影响较大,而受ECAP道次的影响较小。
