Zn-Al合金在压蠕变过程中微观组织变化

Microstructure Evolution of As-cast Zn-Al Alloy during Compressive Creep

通过X射线衍射和SEM研究了铸态ZA27合金在160℃,30MPa时的压蠕变过程中的微观组织变化。结果表明,合金在压蠕变过程中产生了负蠕变,压蠕变促使亚稳相η′相的分解和四相转变的产生,即:α+ε→Τ′+η,四相转变导致合金体积膨胀从而引起负蠕变。随着压蠕变量的增大,合金的微观组织由片层状组织向球形组织变化,压蠕变诱发了合金在热处理时效过程中的相变。

The microstructural evolution of as cast ZA27 alloy wa s investigated during compressive creep under 30 MPa at 160 ℃ by means of X ra y diffraction and SEM. The results showed that compressive creep induced decompo sition of a metastable η′ phase and the occurrence of a four phase transforma tion, α+ε→T+η, with volume expansion during testing, resulting in negativ ecreep in the alloy. The lamellar microstructure evolved into spheroidal microst ructure in the alloy with the increase in compressive creep strain, which provid ed an evidence of phase transformation during aging process.