Minghui CAI
,
Hua DING
,
Jiansu ZHANG
,
Long LI
金属学报(英文版)
doi:10.1016/S1006-7191(08)60076-9
Isothermal transformation (TTT) behavior of the low carbon steels with two Si contents (0.50 wt pct and 1.3 wt pct) was investigated with and without the prior deformation. The results show that Si and the prior deformation of the austenite have significant effects on the transformation of the ferrite and bainite. The addition of Si refines the ferrite grains, accelerates the polygonal ferrite transformation and the formation of M/A constituents, leading to the improvement of the strength. The ferrite grains formed under the prior deformation of the austenite become more homogeneous and refined. However, the influence of deformation on the tensile strength of both steels is dependent on the isothermal temperatures. Thermodynamic calculation indicates that Si and prior deformation reduce the incubation time of both ferrite and bainite transformation, but the effect is weakened by the decrease of the isothermal temperatures.
关键词:
Low carbon steel
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null
,
null
,
null
,
null
王建鹏
,
李伟
,
刘平
,
马凤仓
,
刘新宽
,
陈小红
,
何代华
中国有色金属学报
采用不同Si含量的TiSi复合靶和Cr靶,用射频磁控溅射工艺在Si基底片上沉积不同Si含量的CrN/TiSiN纳米多层膜.采用X射线衍射仪(XRD)、高分辨透射电子显微镜(HRTEM)和纳米压痕仪研究Si含量对CrN/TiSiN纳米多层膜显微结构和力学性能的影响.结果表明:随着Si含量的增加,CrN相的结晶程度先增加后降低,涂层的力学性能先提高后降低,当n(Si)∶n(Ti)=7∶18时获得最高硬度为31.5GPa.HRTEM观测表明,在n(Si)∶n(Ti)=7∶18时,TiSiN层在CrN层的模板作用下呈面心立方结构,并且与CrN层形成共格外延生长结构;当n(Si)∶n(Ti)=11∶14时,TiSiN层总体呈非晶结构,与CrN层的共格外生长结构被破坏.硬度的升高主要与TiSiN与CrN形成共格外延生长结构有关.
关键词:
CrN/TiSiN纳米多层膜
,
Si含量
,
显微结构
,
力学性能
,
外延生长
宋佩维
材料热处理学报
采用光学显微镜(OM)、扫描电镜(SEM)、X射线衍射仪(XRD)和拉伸试验机研究了Si含量变化对Mg-4Al-1Zn-xSi(x=0.5,1.0,2.0,质量分数,％,下同)合金显微组织和力学性能的影响.结果表明:随着Si含量的增加,合金中的α-Mg基体组织逐渐细化;β-Mg17Al12相由点状(块状)逐渐转变为网状分布于晶界上;大量粗大的汉字状Mg2Si相沿晶界或穿晶分布.Si含量从0.5％增加到1.0％和2.0％时,α-Mg基体晶粒的平均尺寸从25μm分别细化到20μm和10 μm;汉字状Mg2 Si颗粒的平均尺寸从5 μm分别增大到10μm和100 μm;合金的硬度逐渐提高;其抗拉强度、屈服强度和伸长率先降低后升高;合金拉伸断裂形式为准解理脆性断裂.
关键词:
Mg-4Al-1Zn-xSi合金
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Si含量
,
显微组织
,
力学性能
