摘要
与压铸Mg合金试样AZ91HP-F相比，压铸后经固溶处理的Mg合金AZ91HP-T4的硬度和屈服强度降低，延伸率、抗拉强度显著提高、抗拉强度与屈服强度比（σb／σ0.2）由压铸态的1.59上升至2.16．固溶处理后再经时效处理的Mg合金AZ91HP-T6的延伸率稍微降低．屈服强度和抗拉强度则显著提高，平均硬度值由压铸态的HB74上升至HB98．三种状态Mg合金的扫描电镜、X射线衍射和X射线能谱分析结果显示，AZ91HP中的主要第二相是固溶Zn的β－Al12Mg17相，这些相铸态时呈网状分布在α-Mg的固溶体晶界，固溶处理后溶入基体，时效过程中再次沿晶界析出，并形成片层胞状组织．β－Al12Mg17的溶解、析出和形态转变是Mg合金AZ91HP-T6时效强化的主要原因。
Comparing with the magnesium die-casting alloy AZ91HP-F, hardness and yield strength of magnesium alloy AZ91HP-T4 decrease through solution treatment after high pressure die-casting, and the elongation, tensile strength as well as tensile to yield ratio (σb/σ0.2) increase to 2.16 from 1.59 of as die-casting. After aging treatment, a little fall of elongation of alloy AZ91HP-T6 has happened, but its yield and tensile strength are obviously enhanced, even more the average value of hardness increases to HB 98 from HB 74 of as die-casting. By using scanning electron microscope, X-ray diffractometer and X-ray energy dispersive spectroscopy, it is shown that the main second phase in AZ91HP alloy is Zn containing β-Al12Mg17, which distributed along the grain boundaries as net microstructure, dissolved in substructure after solution treatment and precipitated along grain boundary again with aging, and formed the lamella shaped cells microstructure. The solution, precipitation and morphology variation of,β-Al12Mg17 can be used in explaining the rule of age-strengthening of Mg based alloy AZ91HP-T6.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
1999年第8期869-873,共5页
Acta Metallurgica Sinica
关键词
热处理
力学性能
镁合金
固溶
时效
magnesium alloy, heat treatment, mechanical property
