摘要
采用金属型重力铸造工艺制备了Mg-Gd-Y-Zn-Zr耐热稀土镁合金发动机活塞,对充型和凝固过程中出现的各种缺陷进行分析,通过对成形工艺的改进消除了缺陷。结果表明,增大浇道的截面积,可以减少活塞的裙部、销孔和补缩冒口产生的浇不足缺陷;增加活塞销孔处壁厚,同时提高模具预热温度至250℃,可以减少活塞销孔处及裙部冷隔缺陷;去除浇道附近的补缩冒口,可以减少夹渣及冷隔缺陷的产生。铸态Mg-Gd-Y-Zn-Zr合金活塞本体组织中大量的第二相分布于晶界处,经过T6处理后部分固溶到基体中,使T6处理后活塞裙部硬度(HV)可达到158。
Heat resistant Mg-Gd-Y-Zn-Zr magnesium alloy engine piston was produced by metal gravity casting.Various defects encountered in the filling and solidification process were analyzed and eliminated by modifying the processing technology.The results show that the misrun defects in the piston skirt,piston top and feeding riser can be eliminated by increasing the cross-sectional area of runner.The coldshut defects in the piston pin-hole and skirt can be prevented by increasing the wall thickness of piston pin-hole and improving the preheating temperature to 250 ℃.The slag and cold-shut defects in the filling process can be inhibited by deleting the feeding riser near the runner.Amounts of secondary phases are distributed along grain boundary in the as-cast microstructure of Mg-Gd-Y-Zn-Zr alloy piston.Some secondary phases are dissolved into theα-Mg matrix after T6 treatment,so the Vichers-hardness of piston skirt reaches 158.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2015年第12期1322-1325,共4页
Special Casting & Nonferrous Alloys
基金
国家自然科学基金资助项目(51404082)
黑龙江省自然科学基金资助项目(E201442)
黑龙江省教育厅科学技术研究项目(12531116)
哈尔滨市创新人才研究专项资金项目(2013RFQXJ137)
哈尔滨理工大学青年拔尖创新人才培养计划资助项目(201510)
关键词
稀土镁合金
活塞
成形工艺
重力铸造
组织
Mg-RE Magnesium Alloy
Piston
Processing Technology
Gravity Casting
Microstructure
作者简介
第一作者简介：胡茂良，男，1980年出生，教授，哈尔滨理工大学材料科学与工程学院，哈尔滨（150040），电话：045186392501，E-mail：humaoliang@hrbust．edu．cn
