同步和异步轧制AZ31镁合金板材的织构及力学性能

采用同步轧制(NR)和异步轧制(AR)工艺对AZ31镁合金挤压板材进行了轧制,研究了轧制过程中组织和织构的演化,以及总压下量和异步比对轧材组织、织构和力学性能的影响。结果表明,在压下量为3%～15%的范围内,同步轧制与异步轧制板材在晶粒尺寸以及均匀性上有相似的变化趋势。轧制过程中,在变形初期,随压下量的增加,孪晶数量不断增加,孪晶使同步轧制与异步轧制板材中晶粒取向都发生偏转,即C轴趋向于垂直于法向(ND),从而使初始挤压板材的丝织构强度减弱;而当压下量达到24%时,孪晶大量减少或消失。在压下量为3%～24%的范围内,同步轧制对板材力学性能的影响并不明显,峰值应变呈交替变化;异步轧制板材在压下量达到24%左右时,表现出了良好的塑性变形能力,抗拉强度达到309MPa,峰值应变达到0.163。

Texture and Mechanical Properties of AZ31 Magnesium Alloy by Asynchronous Rolling

It was investigated that microstructure,texture evolution during rolling process,and influences of total reduction and asynchronous ratio on microstructure,texture and mechanical properties of AZ31 magnesium alloy sheet which processed by normal rolling(NR) and asynchronous rolling(AR) technology.The results show that,when the total reduction ratio is in a range of 3%~15%,the grain size and uniformity in both NR sheets and AR sheets exhibit similar change trend.During the initial stage of rolling,with the increase of reduction,the number of twins is raised,which results in the grain orientation deflection in NR and AR rolled sheets.Namely,axis C of grains tended towards the normal direction(ND),decreasing the silk texture in the extruded sheet.When the total reduction ratio reaches 24%,twins are greatly decreased and or even disappeared.When the total reduction ratio is in a range 3%~24%,the influence of NR rolling on the mechanical properties of the AZ31 magnesium alloy sheets can be neglected.While total reduction ratio reaches about 24%,asynchronous rolled sheets present acceptable plastic performance,and the tensile strength reaches 309 MPa,and the peak strain is 0.163.