摘要
采用光学显微镜和扫描电子显微镜对不同腐蚀剂腐蚀后的Mg-Nd-Zn-Zr镁合金铸态显微组织进行观察。结果表明,Mg-NdZn-Zr合金的铸态组织主要由α-Mg和晶界处的Mg_(12)(Nd,Zn)两相组成,另外还有小块状Mg12(Nd,Zn)相及近圆形的富Zr相区域。1号传统腐蚀剂(4 m L硝酸+96 m L乙醇)可较好显示组织;经2号腐蚀剂(12 g苦味酸+80 m L乙酸+80 m L蒸馏水+350 m L乙醇)腐蚀5 s和10 s后,组织发黑,晶界不明显,但可部分显示出富Zr相区,延长腐蚀时间到20 s,晶粒显现出来,发黑现象得到缓解,富Zr区域明显,但晶界附近出现大量气泡;3号腐蚀剂(60 m L乙二醇+20 m L乙酸+19 m L蒸馏水+1 m L硝酸)腐蚀组织表明,其对晶粒的显示效果明显好于2号,然而很难观察到富Zr区域。
Microstructure of as-cast Mg-Nd-Zn-Zr magnesium alloy etched by different etchant was investigated by means of the optical microscopy（OM） and scanning electron microscopy （SEM）. The results show that the microstructure of as-cast Mg-Nd-Zn-Zr magnesium alloy is mainly composed of two phases that are α-Mg and Mg12（Nd, Zn） at the grain boundary. In addition, there are zones of small lump Mgl2（Nd, Zn） phase and a nearly circular Zr-rich phase. The No. 1 traditional etchant （4 mL nitric acid ＋ 96 mL ethanol） can better display the microstructure. After etched by No. 2 etchant （12 g picric acid ＋ 80 mL acetic acid ＋ 80 mL distilled water ＋ 350 mL ethanol） for 5 s or 10 s, the microstructure becomes dark, and the grain boundary is not clear but could show the zone of Zr-rich phase. With etching time increaseing to 20 s, grains can be exposed and the darkness be weaken, the Zr-rich zones be evident but abundant bubbles come out around the grain boundary. The microstructure etched by the No. 3 etchant （60 mL glycol ＋ 20 mL acetic acid ＋ 19 mL distilled water ＋ 1 mL nitric acid） display that the effect of No. 3 on grains is clearly better than No. 2, nevertheless the Zr-rich zones is still hard to observe.
出处
《金属热处理》
CAS
CSCD
北大核心
2016年第6期168-172,共5页
Heat Treatment of Metals
基金
高性能镁合金制备及精深加工研发及产业化(0211002411030/004)
