机械搅拌对ZA27合金组织的影响

研究了机械搅拌对ＺＡ２７合金组织的影响，同时给出了温度与固相率的对应值．结果表明，在机械搅拌下，ＺＡ２７合金的凝固组织为等轴晶或玫瑰状聚集体，由枝晶残体和棒状与球状粒子组成，且随着温度的降低，初生相逐渐球状化和分散化；初生晶非树状化是由于枝晶臂颈缩折断，合并生长所致；机械搅拌加剧了晶臂颈缩，促进了颈缩折断；固相间存在着合并生长

Effects of mechanical stirring on microstructure of ZA27 alloy

The effects of mechanical stirring on the microstructure of ZA27 alloy are investigated. Simultaneously, the qualitative relation of the temperatures and solid fractions is given. The results shows that, by means of stirring the primary crystals of the alloy are equiaxed grains and rosette agglomerations composed of ellipsoidal and spheroidal paricals mixed with residual dendrites. In addition the primary crystals gradually become more rounded spheroid and uniform with decreasing temperatures. The formation of nondendrites is due to the neck shrinking, breaking and joining of the dendrite arms. The mechanical stirring intensifies the neck shrinkage of the dendrite arms and accelerates their breakdown. There is coalescing between solid phases.