CAJ | 학술논문

通过调整元素Y的含量,制备了多种Mg-Y-RE-Zr镁合金,对合金不同状态下微观组织和力学性能进行了分析和测试.结果表明,不同合金晶界上的化合物以Mg24Y5,Mg41Nd5,Mg5Gd等为主,随着元素Y含量的增加,晶界上的化合物数量和尺寸增加,晶粒平均尺寸变化较小,保持在50～60μm;经过均匀化处理(535℃×24 h)后,合金中化合物的分布由铸态时连续的岛状分布变为弥散细小的颗粒状分布,Mg5Gd相基本上全部分解并溶入基体中,合金中弥散分布的点状颗粒相主要为Mg24Y5和Mg41Nd5相;经过挤压变形后,合金的组织得到细化,平均晶粒尺寸在20μm左右,合金的抗拉强度、屈服强度和伸长率都有大幅度的提高,其中Mg-5Gd-5Y-3Nd.0.5Zr合金表现出了较好的综合力学性能;在设计的合金中,元素Y的含量(质量分数)应控制在5%以下.
통과조정원소Y적함량,제비료다충Mg-Y-RE-Zr미합금,대합금불동상태하미관조직화역학성능진행료분석화측시.결과표명,불동합금정계상적화합물이Mg24Y5,Mg41Nd5,Mg5Gd등위주,수착원소Y함량적증가,정계상적화합물수량화척촌증가,정립평균척촌변화교소,보지재50～60μm;경과균균화처리(535℃×24 h)후,합금중화합물적분포유주태시련속적도상분포변위미산세소적과립상분포,Mg5Gd상기본상전부분해병용입기체중,합금중미산분포적점상과립상주요위Mg24Y5화Mg41Nd5상;경과제압변형후,합금적조직득도세화,평균정립척촌재20μm좌우,합금적항랍강도、굴복강도화신장솔도유대폭도적제고,기중Mg-5Gd-5Y-3Nd.0.5Zr합금표현출료교호적종합역학성능;재설계적합금중,원소Y적함량(질량분수)응공제재5%이하.
Microstructure and mechanical properties of Mg-5Gd-3Nd-0.5Zr alloys containing different Y con-tents were investigated under different conditions. The results reveal that compounds at grain boundary in the alloys are mainly composed of Mg24Y5, Mg41Nd5 and Mg5Gd, furthermore, with increasing in Y content, the numbers and grain size of the com-pounds at the grain boundary are increased, however, average grain size still keeps approximately 50～60μm, showing slightly change. After homogenization treatment at 535℃ for 24 hours, compounds in the al-loys are converted from continuous island structure at as-cast state into dispersively fine particles, where dis-persively distributed particles in the alloys are mainly composed of Mg24 Y5 and Mg41 Nd5 phase while Mg5 Gd phase is mostly decomposed and dissolved into the ma-trix. After extrusion, the microstructure with approx-imately 20 μm in average grain size can be observed in the alloy, and tensile strength, yield strength and e-longation of the alloys can be greatly improved, in which desirable comprehensive mechanical properties can be observed in Mg-SGd-SY-3Nd-0.5Zr. The Y content should be controlled less than 5% in weight in designed alloys.