摘要
将SiO2颗粒填入AZ61镁合金基体上预先开出的沟槽中,利用搅拌摩擦工艺(FSP)成功地将颗粒均匀地搅拌进镁合金中。利用扫描电镜(SEM)观察了试样搅拌区颗粒分布情况,分别对高温退火和高温拉伸试样的晶粒长大情况进行了观察,测量了试样搅拌区及其附近区域的硬度,利用扫描电镜进行了断口形貌分析并对试样高温变形机制进行了分析。结果表明:大部分SiO2颗粒被均匀地搅拌进镁合金中,仅有少量的颗粒以聚集块形式存在;未掺入SiO2颗粒的搅拌摩擦试样搅拌区平均硬度为HV78,而掺入SiO2颗粒的试样搅拌区平均硬度为HV110,提高了HV30左右;合金中的SiO2颗粒有效地抑制了静态退火、高温拉伸和搅拌摩擦过程中的晶粒长大,使其保持在3μm以内;试样在400℃下以3×10-1s-1的应变速率拉伸得到的伸长率最大,达到了453%,实现了材料高应变速率下的超塑性。
FrictiOn stir processing （17SP） was applied to incorporate SiO2 particles that were filled in the grooves of the matrix alloy in advance into the AZ61 magnesium alloy uniformly. The distribution of particles in the stirred zone of specimens was investigated by scanning electron microscopy （SEM）. The grain growth conditions of the specimens annealed and drew at high temperature were investi- gated respectively. The hardness of the stirred zone and its vicinity of specimens were measured.＇ The fracture morphology analysis was conducted by SEM and the high-temperature deformation accommodation mechanism of the alloy was also analyzed. The results indica- ted that most SiO2 particles were stirred into the magnesium alloy uniformly except little particles that were presented as clustered parti- cles. The hardness of magnesium alloy frictio~ stir processed with SiO2 particles was about HV30 higher than that of the same alloy fric- tion stir processed without Si02 particles, and the hardness of the former and the latter were HV110 and HV78 respectively. The SiO： particles incorporated into the AZ61 magnesium alloy could effectively suppress grain growth during static annealing, high temperature tensile and friction stir processing, and meanwhile maintained the grains less than 3 Ixm in size. The specimens exhibited high strain rate superplasticity with a maximum elongation of 453% at 400 ℃ and a strain rate of 3 x 10-1 s- 1.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2015年第10期948-954,共7页
Chinese Journal of Rare Metals
基金
陕西省教育厅科学研究计划项目(15JK2172)资助
