摘要
研究了可热处理铸造Al-Si系合金的时效行为。发现合金的时效硬化曲线表现出不同的单、双峰硬化特征。透射电镜(TEM)、高分辨电镜(HRTEM)观察和差示扫描量热仪(DSC)分析证实,时效硬化的单、双峰现象与合金的时效析出序列密切相关,AlSiMg合金的GP Ⅱ区和亚稳定相的形成部分重叠交叉进行,造成了时效曲线上的硬度平台;在AlSiCu合金的时效过程中,GP区向亚稳定相的直接转变,造成了时效曲线上的单硬度峰。而A354和AlSiCuMg合金中GP Ⅱ区向亚稳相的转变有明显的时间间隔,使合金时效硬化曲线出现了双硬度峰现象。
The age-hardening characteristics of heat-treatable Al-Si-base cast alloys have been investigated in this paper. When aging treatment exceeds a fixed temperature, two and one hardness peaks present in ageing curves of different tested alloys respectively. The result of TEM observation and DSC analyses proved that the characteristics of age-hardening curves are related to the precipitation sequences of tested alloys. For A354 alloy, obvious interval during the transition from GPII zones to meta-stable phases is the main reason for two peaks aging, the first hardness peak of age hardening curve is attained depending on the high-density GPII zone, while the second one is acquired in terms of theta' and beta'mate-stable grains.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2004年第2期171-175,共5页
Rare Metal Materials and Engineering
关键词
铸造铝合金
时效强化
显微组织
DSC曲线
双峰时效
cast aluminum alloy
age hardening
microstructure morphology
DSC curve
tow-peaks aging
