等通道转角挤压Al一Mg—Si—Sc合金的低周疲劳行为

Low Cycle Fatigue Behavior of AI--Mg--Si--Sc Alloy Processed By Equal Channel Angle Pressing

针对经过常规热挤压的Al-0．8%Mg-O．6％Si一0．3%ASc合金进行不同道次和路径的等通道转角挤压，采用的等通道转角挤压工艺为1道次和2道次A路径、＆路径和C路径。对等通道转角挤压制备的Al－0．8%Mg－0．6％Si－0．3％Sc合金进行应室温低周疲劳实验，研究了等通道挤压Al一0．8%Mg－0．6％Si－0．3％Sc合金的疲劳行为。结果表明，在低周疲劳加栽条件下，等通道转角挤压Al—Mg—Si—Sc合金可表现为持续循环硬化或初期循环硬化后期循环稳定。合金的弹性应变幅、塑性应变幅与断裂时的栽荷反向周次之间的关系可分别用Basquin和Coffin－Manson公式描述。

One pass and two passes of equal channel angle pressing ECAP with routes A, Bc and C were conducted for the conventionally hot--extruded A1--Mg--Si--Sc alloy. Through performing the total strain controlled fatigue experiments at room temperature, the fatigue behavior of the ECAPed A1--Mg--Si--Sc alloy was investigated. The experimental results show that, Under low--cycle fatigue loading condition, the ECAPed A1--Mg--Si--Sc alloys can exhibit the continuous cyclic strain hardening or initial cyclic strain hardening followed by cyclic stability. For the ECAPed A1--Mg--Si--Sc alloy, the re- lations between elastic strain amplitude, plastic strain amplitude and reversals to failure can be described by Basquin and Coffin -- Manson equations, respectively.