摘要
通过SEM、TEM和蠕变试验机研究不同温度下Mg-8Gd-2Nd-0.5Sb-0.6Zr(质量分数/%)合金高温蠕变行为,分析其组织演变,并通过计算合金的蠕变激活能分析蠕变机制。结果表明:加载应力10 h后,合金进入稳态蠕变阶段,随着温度升高蠕变性能差异明显增大;高温高应力情况下,组织上观察不到网状析出相,滑移线较多,存在孪晶,位错密度较高,此时网状析出β′相已经完全转变为颗粒状β相;蠕变温度在200、250、300℃下的应力指数为3.5、4.6和5.8,蠕变激活能为77.8、86.8、99.6 k J/mol。合金低温时受位错交滑移机制控制;高温时受扩散机制控制。
The high temperature creep behavior of Mg-8Gd-2Nd-0.5Sb-0.6Zr（mass fraction/%）alloy was studied by SEM,TEM and creep testing machine under different temperature,the microstructure evolution was analyzed,and through the calculation of creep activation energy of alloy,the creep mechanism was analyzed. The results show that after 10 h loading,the alloy enters into the steady-state creep stage,the difference of creep properties was obviously increased with temperature increasing. Under the condition of high temperature and high stress,no cellular precipitates are observed,there are more slip lines and twins,dislocation density is higher,the cellular precipitated beta phase has completely transformed into granular beta phase. Under the creep temperature of 200,250,300 ℃,the stress index are 3.5,4.6 and 5.8,respectively;creep activation energy is 77.8,86.8,99.6 k J/mol,respectively. Alloy is controlled by dislocation cross-slip mechanism at low temperature,and by diffusion mechanism at high temperature.
作者
邓璘
DENG Lin(Department of Automobile Engineering, Chongqing College of Electronic Engineering, Chongqing 401331, China)
出处
《兵器材料科学与工程》
CAS
CSCD
北大核心
2017年第2期65-68,共4页
Ordnance Material Science and Engineering
基金
重庆市教委科学技术研究项目(KJ1503005)
