摘要
旨在优化AZ91镁合金凝固组织,通过OM和XRD设备研究了不同离心压力和冷却速度对AZ91镁合金凝固组织演变的影响,结果表明,随着离心压力的增大,合金晶粒尺寸细化,第二相β(Mg12Al17)析出量减少,不保温试样,β相形态由粗大连续网状向细小断续状转变,保温试样,β相为粒状弥散分布晶内,压力增大,颗粒数量减小,粒径细化.同等凝固压力下,增大冷速,一次β相析出量增多,二次β相析出量减少.XRD分析表明,增大离心压力β相峰值略微减弱,α-Mg的晶格常数减小.
Solidification microstructure evolution of magnesium alloy AZ91 under different centrifugal pressure and cooling rate were explored through OM and XRD to optimize solidification micmstructure of AZ91 alloy , With the increasing of centrifugal pressure, the grain size and precipitation of second phase β-MgnA117 was decreased, the morphology of β turned from coarse continuous networks to thin interruption in the sample without heat preservation, while in the sample with heat preservation, granular β phase distributed within the grains. The number of β was reduced , and the size of β was refined with increasing centrifugal pressure. With the increase of cooling rate under same pressure, more primary β precipitated, but less secondary β precipitated. Result of XRD showed that the peak value of β weakened slightly and the lattice constant of α-Mg decreased with increasing pressure.
出处
《材料科学与工艺》
EI
CAS
CSCD
北大核心
2015年第6期125-128,共4页
Materials Science and Technology
基金
陕西省工业攻关项目(2014K08-16)
陕西省教育厅专项科研计划项目(14JK1411)
陕西省社发重点合作单位项目(2012KTJD02-01)
关键词
离心压力
冷却速度
AZ91镁合金
凝固组织
centrifugal pressure
cooling rate
AZ91 magnesium alloy
solidification microstructure
