在一次性充入0.01%(体积分数)HFCl34a/N2/空气保护气氛的密封熔炼炉中,研究了气氛中空气含量、表面搅拌和保温时间对AZ91D镁合金在760℃下保护效果的影响和气氛对熔炼坩埚内壁的腐蚀情况,并对表面膜形貌、厚度和成分进行了研究.研究结果表明,气氛中空气分压为8.0 kPa时,经过10 h保温,AZ91D熔体依然被保护,表面搅拌不影响保护效果.随着气氛中空气分压从2.3 kPa增加到80.0 kPa,AZ91D表面平整度降低,当空气分压为80.0 kPa时,表面膜分为两层,最表层呈网状;表面膜中氧的原子分数从11.98%升高到26.62%,C的原子分数从0.98%降低到0,表面膜厚度从1.1μm增加到1.7μm,熔炼坩埚内壁从没有红锈腐蚀到大片氧化铁皮脱落.因此在密封熔炼炉含0.01%(体积分数)HFC134a气氛中熔炼AZ91D,气氛中空气含量越少,金属镁的氧化量越少.
参考文献
| [1] | 中国机械工程学会铸造专业学会.铸造手册:铸造非铁合金[M].北京:机械工业出版社,1993 |
| [2] | Blandin J J.Ignition resistance of various magnsium alloys[A].America:The MineralsMetals & Materials Society,2004:235-240. |
| [3] | Zhang Z.Effect of inhibitor gas on mould-magnesium reactions in investment casting[A].Germany:The MineralsMetals & Materials Society,2004:197-202. |
| [4] | King J F;Swinton.Environmental Challenges Facing the Magnesium Industry-SF6 Replacement[A].America:International Magnesium Association,2003:10-16. |
| [5] | Cashions S P;Rickeus N J;Hayes P C .Characterization of Protective Surface Films Formed on Molten Magnesium Protected by Air/SF6 Atmospheres[J].Joumal of Light Metals,2002,2(01):37-42. |
| [6] | Cashions S P;Ricketts N J;Hayes P C .The Mechanism of Protection of Molten Magnesium by Cover Gas Mixtures Containing Sulphur Hexafluoride[J].Journal of Light Metals,2002,2(01):43-47. |
| [7] | Pettersen G;Ovrelid E;Tranell G et al.Characterization of the Surface Films Formed on Molten Magnesium in Different Protective Atmospheres[J].Materials Science and Engineering,2002,A332:285-294. |
| [8] | Fruehling J W.Protective Atmospheres for Melting Magnesium Alloys[J].AFS Transactions,1988(04):159-164. |
| [9] | Brochot .Method for rotecting a nonferrous liquid metalin articular,liquid magnesium against oxidation and ignition[P].FR 2775209,1988-06-29. |
| [10] | 李华伦 .镁及其合金在含SF6气氛中的高温氧化特性[J].西北工业大学学报,1984,2(01):77-89. |
| [11] | 巴林 Ⅰ.纯物质热化学数据手册[M].北京:科学出版社,2003 |
上一张
下一张
上一张
下一张
计量
- 下载量()
- 访问量()
文章评分
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%