摘要
采用拉伸试验机、金相显微镜、XRD、SEM以及EMPA等手段对合金元素总含量超过15%(质量分数,下同)的新型超高强Al-11.7Zn-2.2Mg-2.0Cu-0.12Zr铝合金不同固溶温度处理后的组织与性能变化规律进行了研究。结果表明:晶内的固溶度随温度升高逐渐增加,在474℃时基本达到稳定状态,约有99%的Zn、Mg以及75%的Cu溶入晶内,其余的合金元素富集在晶界第二相内,此时,第二相主要由含Cu的η以及T相构成;合金的最佳固溶温度为474℃,此时合金的抗拉强度(σb)为688 MPa、延伸率(δ)为8%;温度为476℃时,合金局部区域出现轻微过烧,导致延伸率迅速降低;断口分析显示,随固溶温度的提高,再结晶程度增加,晶界第二相数量减少,合金的拉伸断口由较低温度时的沿晶+穿晶混合断口转变为较高温度时的沿晶断口为主。
Effects of solution temperature on solid solubility, tensile properties, microstructure and fractography of a new Al-Zn-Mg-Cu-Zr aluminum alloy were studied by tensile testing, optical microscopy, XRD, SEM and EPMA. The results indicate that the solid solubility of the matrix increases with the increasing of temperature, and it reaches stable state at 474°C when about 99 wt% Zn, Mg and 75 wt% Cu enter into the matrix, and the residual elements enrichment in the second phase particles locate on grain boundary. The optimal solution temperature is 474°C; at the same time, the tensile strength of forge can get up to 688 MPa, and elongation is 8%. At 476°C, the slight over-burned in local region is observed, which lead to the decrease of elongation rapidly. It is found that the tensile fractography is affected by the volume fraction of residual particles and the recrystallization level of deformed grains. With the temperature increasing, the fractography transforms from intergranular cracking mixed dimple-type transgranular cracking to intergranular cracking.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2016年第4期1040-1044,共5页
Rare Metal Materials and Engineering
