AZ91-0.75Ce稀土镁合金差热分析及β相形成规律

张燕龙; 杨伟; 周珍珍; 陈胜娜; 陈寿辉; 夏卫

doi:10.15980/j.tzzz.2014.05.020

轻有色合金 | 浏览量 : 0 下载量: 343 CSCD: 6

导出
分享
收藏
专辑

AZ91-0.75Ce稀土镁合金差热分析及β相形成规律
Differential Thermal Analysis and Formation Regularity of βPhase in AZ91-0.75Ce Rare Earth Magnesium Alloy
2014年34卷第5期页码：541-544
纸质出版日期： 2014 ，
DOI： 10.15980/j.tzzz.2014.05.020

扫描看全文

[1]张燕龙,杨伟,周珍珍,陈胜娜,陈寿辉,夏卫.AZ91-0.75Ce稀土镁合金差热分析及β相形成规律[J].特种铸造及有色合金,2014,34(05):541-544.

Zhang Yanlong, Yang Wei, Zhou Zhenzhen, et al. Differential Thermal Analysis and Formation Regularity of βPhase in AZ91-0.75Ce Rare Earth Magnesium Alloy[J]. Special Casting & Nonferrous Alloys, 2014,34(5):541-544.
[1]张燕龙,杨伟,周珍珍,陈胜娜,陈寿辉,夏卫.AZ91-0.75Ce稀土镁合金差热分析及β相形成规律[J].特种铸造及有色合金,2014,34(05):541-544. DOI： 10.15980/j.tzzz.2014.05.020.

Zhang Yanlong, Yang Wei, Zhou Zhenzhen, et al. Differential Thermal Analysis and Formation Regularity of βPhase in AZ91-0.75Ce Rare Earth Magnesium Alloy[J]. Special Casting & Nonferrous Alloys, 2014,34(5):541-544. DOI： 10.15980/j.tzzz.2014.05.020.

摘要

采用真空感应熔炼方式

研究了稀土元素Ce对AZ91镁合金铸态组织的影响。利用差热分析仪

通过对稀土镁合金熔化和凝固过程进行实时分析

研究了不同冷却速率（10、20、40和80℃/min）条件下β相的形成规律。结果表明

稀土元素Ce有利于细化AZ91合金的基体组织

同时形成Al-Ce化合物相

有效抑制晶界处β-Mg17Al12离异共晶相的形成。此外

Ce含量为0.75%的AZ91合金导致其液相线温度由605℃下降到583℃。近平衡凝固条件下

随冷却速率提高

液固界面前沿溶质扩散不及时

热分析曲线中共晶峰的相对面积不断增加

β共晶相含量逐渐升高。由于冷速的增加缩短了固态相变时间

导致共析转变过程中所形成的层片状β相含量降低。

Abstract

Influences of RE element Ce on as-cast microstructure of AZ91magnesium alloy were investigated by vacuum induction melting method.Then

the melting and solidification processes for rare earth magnesium alloy were analyzed by differential thermal analysis（DTA）with different cooling rates

such as 10K/min

20K/min

40K/min and 80K/min

in order to understand the formation regularity ofβ phase.The results show that Ce element can refine grain size in the microstructure of AZ91alloy and can effectively suppress the occurrence of divorced eutecticβ-Mg17Al12phase in grain boundary as a result of the formation of Al-Ce compound.Addition of 0.75%Ce can decrease the liquidus temperature of AZ91alloy from 605℃to 583℃.Under the condition of near equilibrium solidification

the increase of cooling rate results in insufficient solute diffusion ahead of liquid-solid interface front

which enhances the relative area of eutectic peak in DTA curves and indicates the increase of volume fraction of divorced eutecticβ-Mg17Al12phase.In addition

the lamellar volume fraction for secondary precipitatedβphase is decreased

which can be attributed to the decrease of eutectoid transition time because of higher cooling rate.