不同热轧工艺对ZK61镁合金板材塑性变形的影响

Influence of different hot rolling processes on plastic deformation for ZK61 magnesium alloy plate

针对镁合金因其典型的密排六方结构在室温条件下难以成形的问题,采用多道次同步热轧结合异步温轧的加工工艺,制备了具有高抗拉强度和伸长率的ZK61镁合金薄板,并结合宏观轧制有限元模拟方法详细分析了轧制过程中板材的塑性变形机制。拉伸实验结果表明:随着轧制的进行,板材的各向异性变弱,力学性能不断提升,抗拉强度达到398.9 MPa,伸长率达到30.4%。模拟结果显示:在同步轧制时,最大等效应力值随轧制的进行略微增加,而异步轧制时的最大等效应力值随轧制的进行逐渐降低;同步轧制前几道次的轧件的等效塑性应变并不均匀,但随着轧制的进行和后续的异步轧制,板材的塑性应变逐渐均匀。

For the problem that magnesium alloy was difficult to form at room temperature due to its typical close-packed hexagonal struc-ture,ZK61 magnesium alloy sheet with high tensile strength and elongation was obtained through a combination process of multi-pass syn-chronous hot rolling and asynchronous warm rolling,and combined with the finite element simulation method of macroscopic rolling,the plastic deformation mechanism during the rolling process was analyzed in detail.The results of the tensile test show that as the rolling pro-gresses,the anisotropy of sheet becomes weaker and the mechanical properties continue to be improved,and the tensile strength reaches 398.9 MPa and the elongation reaches 30.4%.The simulation results show that during the synchronous rolling,the maximum equivalent stress value increases slightly as the rolling progresses,while the maximum equivalent stress value during the asynchronous rolling gradual-ly decreases as the rolling progresses.The equivalent plastic strain of rolled piece in the first few passes of synchronous rolling is not uni-form,but as the rolling progresses and the subsequent asynchronous rolling,the plastic strain of sheet gradually becomes uniform.