CAJ | 학술논문

通过SEM、X射线衍射等试验手段,研究了合金元素Cr对Mg-10Zn-2Al-1Cu镁合金显微组织及沉淀析出过程的影响.结果表明,Cr元素能细化试验合金的铸态组织,并能部分打断β-Mg_(17)Al_(12)网状组织,且三元相τ-Mg_(32)(Al,Zn)_(49)、AlMg_4Zn_(11)、CeCuAl_3及颗粒状Al_4Cu_9相在晶内呈弥散析出,并形成新相CrSb_2.试验合金的时效沉淀过程中显微组织的演变过程为:过饱和固溶体→溶质原子偏聚→呈蠕虫状聚集分布的有序相→过渡相→呈(短)杆状或粒状稳定相.合金元素Cr能加速时效初期原子偏聚和晶核形成速度,增加时效后期析出相的稳定性、抑制析出相的长大.
통과SEM、X사선연사등시험수단,연구료합금원소Cr대Mg-10Zn-2Al-1Cu미합금현미조직급침정석출과정적영향.결과표명,Cr원소능세화시험합금적주태조직,병능부분타단β-Mg_(17)Al_(12)망상조직,차삼원상τ-Mg_(32)(Al,Zn)_(49)、AlMg_4Zn_(11)、CeCuAl_3급과립상Al_4Cu_9상재정내정미산석출,병형성신상CrSb_2.시험합금적시효침정과정중현미조직적연변과정위:과포화고용체→용질원자편취→정연충상취집분포적유서상→과도상→정(단)간상혹립상은정상.합금원소Cr능가속시효초기원자편취화정핵형성속도,증가시효후기석출상적은정성、억제석출상적장대.
Effects of Cr on microstructure and precipitation process of Mg-10Zn-2Al-1Cu alloy were investigated by SEM (scanning electron microscope) and XRD (X-ray diffraction). It is found that Cr can refine the microstructure of the alloy by partly brokening the network structure of β-Mg_(17)Al_(12) phase, resulting in the dispersed precipitation of ternary τ-Mg_(32)(Al,Zn)_(49), AlMg_4Zn_(11), CeCuAl_3 phases and Al_4Cu_9 particle and creation of CrSb_2 phase. Evolution of microstructure of the alloy during aging deposition is as follows: supersaturated solid solution→segregation of solute atoms→an vermiculate orderly distributed phase→the transition phase→(short)rod-shaped or granular stability. Cr can accelerate atomic segregation and nucleation rate at early aging and increase the stability of precipitates as well as inhibiting the growth of precipitates at latter aging.