CAJ | 학술논문

AZ80镁合金在380°C挤压之后，分别在170°C和310°C下进行不同时间的时效，以比较析出相的形貌和结构对镁合金屈服不对称性的影响。对沿挤压方向切取的样品在室温下进行单轴拉伸及压缩实验。结果发现，时效样品的拉压屈服不对称显然比未时效挤压样品的弱很多，这是因为时效样品中的孪生发生远少于挤压样品中的。此现象可以通过时效样品中孪生的临界剪切力增量比基面滑移的增量大，而其取向因子却减小使得其发生更困难来证实。镁合金中的拉压屈服不对称性可以通过增加析出相分数来减弱甚至消除。实验结果显示，当合金内析出相分数达到饱和后，拉压不对称性消失。
AZ80미합금재380°C제압지후，분별재170°C화310°C하진행불동시간적시효，이비교석출상적형모화결구대미합금굴복불대칭성적영향。대연제압방향절취적양품재실온하진행단축랍신급압축실험。결과발현，시효양품적랍압굴복불대칭현연비미시효제압양품적약흔다，저시인위시효양품중적련생발생원소우제압양품중적。차현상가이통과시효양품중련생적림계전절력증량비기면활이적증량대，이기취향인자각감소사득기발생경곤난래증실。미합금중적랍압굴복불대칭성가이통과증가석출상분수래감약심지소제。실험결과현시，당합금내석출상분수체도포화후，랍압불대칭성소실。
Samples of AZ80 alloy were hot extruded at 380 °C and aged at temperatures of 170 °C and 310 °C respectively for different periods to compare the effect of precipitate structures on the tensile-compressive yielding asymmetry in magnesium alloy. Uniaxial tension and compression along the extruded direction were carried out at room temperature. It was found that the yielding asymmetry in the aged samples was not as significant as that in the as-extruded samples. This was because twinning occurred less readily in the aged samples. And it was also confirmed by the fact that the increment of the critical resolved shear stress (CRSS) for twinning was higher and the Schmid factor was lower in the aged samples in the presence of precipitate. Thus, it was concluded that the yielding asymmetry could be reduced and even eliminated by increasing the area fraction of the precipitate phase.