【摘要】 本文研究了不同Y含量对Ng—Zn—Zr合金显微组织的影响,并对析出相进行了鉴定,探讨了析出相析出过程及对合金力学性能的影响。研究结果表明,Y含量变化能使合金晶界状况发生变化,当Y含量小于0.94％wt时,可使合金晶界窄化,当Y含量大于0.94％wt后,反而使晶界重新粗化,在三角或四角晶界处出现共晶组织;当Y含量大于0.94％wt时,Y趋向晶界富集,并与在晶界富集的Zn形成颗粒较大的Y—Zn相,对合金力学性能产生不利影响;在该合金中,适当的Y含量(约0.94％wt)可提高合金挤压态下的抗拉强度,其强化机理主要是由于Y能使晶界窄化,金相组织均匀,并能使Y与Mg形成弥散强化相,使晶内产生亚晶等原因所致。更多还原

【Abstract】 The influence of different contents of Y on microstructures of Mg- Zn-Zr-Y alloys was studied. Also,the extracting phases were identified and the extracting process and its influence on the mechanical property of alloy were investigated. The results show that the change in content of Y will cause the change in grain boundary of the alloy. Less than 0.94/wt content of Y can narrow the grain boundary of the alloy. More than 0.94%wt content of Y will widen the grain boundary and form the eutectic of the tee and the cross grain boundaries of the alloy. In this case, the grain boundaries tend to abound with Y and the relatively big particles of Y-Zn phase which can badly influence on the mechanical properties of the alloy will be formed. The suggested content of Y in this kind of alloy is about 0.94%wt. The proper content of Y can narrow the grain boundary even the microstructures and form the disper- sive strengthening phases and the subcrystallines in the alloy. Those effects of Y are the main mechanisms so that alloy was strengthened.更多还原