Al-Zn体系高压扭转过程中的相变机理

Phase Transformation Mechanism of Al-Zn System During High Pressure Torsion

本工作对常温不互溶的Al-Zn体系进行了高压扭转下的机械合金化研究。将0.03 mm厚的纯Al和纯Zn交替堆叠,在3 GPa的压力下进行50圈的高压扭转处理。结果表明,高压扭转处理的Al-Zn合金中产生两种类型的相变,即晶体到非晶的相变,以及密排六方到面心立方的相变。局部高密度位错可能是Al-Zn合金从晶态转变到非晶态的主要原因,而HCP→FCC相变则归因为密排面原子沿晶界产生的Shockley不全位错的滑动。此外,本工作为深入研究Al-Zn合金的固态相变提供了一种新的途径,为提高铝锌合金的力学性能提供了新的思路。

In this work,the mechanical alloying of the immiscible Al-Zn system at room temperature under high pressure torsion was studied.Mechanical alloying via high pressure torsion(HPT)was studied for the immiscible Al-Zn system at room temperature.Stacks of alternating 0.3 mm thick sheets of pure Al and Zn were subjected to HPT processing at a pressure of 3 GPa for 50 revolutions.The results show that two phase transformation occurred in the Al-Zn alloy after HPT process,the phase transformation from crystal to amorphous,and the phase transition from hexagonal close-packed to face-centered cubic.High local dislocation density may primarily accounted for the crystalline-to-amorphous transformation in Al-Zn alloy and the phase transformation is attributed to the sliding of Shockley partial dislocations generated at the Al-Zn grain boundaries.Moreover,this work provides a new approach for the in-depth study of the solid phase transformation of Al-Zn alloys.It may also shed lights on improving the mechanical properties of the HPT processed Al-Zn alloys.