吴孟海
,
张兴平
,
许德美
,
赵洪章
,
李陈
稀有金属
doi:10.3969/j.issn.0258-7076.2007.04.007
为了研究Ta-10W合金在高温下的塑性变形机制,对再结晶状态的Ta-10W合金棒材在1000～2000 ℃进行了高温力学性能测试后,对该合金在各个高温下形成的拉伸断口进行了研究分析.研究表明:Ta-10W合金从1000～2000 ℃的高温塑性变形呈现出金属在高温下变形的一般规律:随着温度的升高,Ta-10W合金的塑性变形机制由以滑移为主的变形机制向以晶界滑动和转动为主的变形机制转变;该合金在高温变形中存在着加工硬化和动态回复或再结晶两个相反的过程,且动态再结晶对塑性的贡献高于动态回复.
关键词:
Ta-10W合金
,
高温断口分析
,
晶界滑动
,
动态回复和再结晶
,
塑性变形
吴孟海
,
李树清
,
许德美
,
赵洪章
稀有金属材料与工程
测试了退火态Ta-10W合金棒材从1000℃～2000℃的高温力学性能.室温下,Ta-10W合金具有较高的强度和塑性,随着温度的升高,极限抗拉强度以较快的速度下降,而屈服强度和弹性模量下降较慢,延伸率和断面收缩率稍有上升.在1600℃和2000℃时的拉伸断口中均出现了一种较为特殊的新型韧窝,特别是在1600℃同时出现的两种不同的韧窝,使该合金的塑性达到最高值.分析表明,Ta-10W合金屈服强度和弹性模量随温度的升高下降较为缓慢的原因是动态应变时效和动态再结晶综合作用的结果.
关键词:
Ta-10W合金
,
高温拉伸性能
,
断口分析
,
动态再结晶
,
动态应变时效
吴孟海
,
李树清
,
许德美
,
赵洪章
稀有金属材料与工程
测试了退火态Ta-10W合金棒材从1000℃～2000℃的高温力学性能.室温下,Ta-10W合金具有较高的强度和塑性,随着温度的升高,极限抗拉强度以较快的速度下降,而屈服强度和弹性模量下降较慢,延伸率和断面收缩率稍有上升.在1600℃和2000℃时的拉伸断口中均出现了一种较为特殊的新型韧窝,特别是在1600℃同时出现的两种不同的韧窝,使该合金的塑性达到最高值.分析表明,Ta-10W合金屈服强度和弹性模量随温度的升高下降较为缓慢的原因是动态应变时效和动态再结晶综合作用的结果.
关键词:
Ta-10W合金
,
高温拉伸性能
,
断口分析
,
动态再结晶
,
动态应变时效
翟云霄
,
古一
,
黄璜
,
赵培新
,
黄继武
,
夏长清
材料导报
doi:10.11896/j.issn.1005-023X.2016.24.020
采用多弧离子镀技术在金属钛表面成功制备出连续致密且厚度均匀的α-Ta 相 Ta-10W涂层。在900℃下分别对涂层进行高温氧化和真空扩散处理,通过 XRD、SEM、EDS等分析测试手段对涂层的抗氧化性能及元素扩散行为进行研究。结果表明：在高温氧化过程中,存在氧化和扩散双重作用,涂层与基体间发生相互扩散且涂层表面形成氧化膜,致使涂层脆化,但涂层/基体界面处氧化不明显,说明Ta-10 W涂层对基体起到了有效的抗氧化作用；在真空扩散过程中,Ta向基体中扩散较为剧烈且沿着逐渐趋直的α-Ti晶界进行扩散。
关键词:
纯钛
,
多弧离子镀
,
Ta-1 0 W涂层
,
高温氧化
,
真空扩散
卢旭东
,
王复利
材料研究学报
doi:10.11901/1005.3093.2016.163
采用X射线衍射(XRD),扫描电镜(SEM)及能谱(EDAX)等方法,研究了Ni-4.66Cr-5.87Co-7.54Mo-2.90W-4.97Ta-6.32Al合金在900℃和1000℃的高温氧化行为.结果表明,合金氧化动力学曲线遵循氧化初期氧化增重速率较快,氧化期间氧化动力学曲线呈波浪式变化,且呈现氧化温度越高波浪式越明显的特征;氧化300 h后合金表面氧化物膜分为2层,外层氧化物为NiO、Ni2Cr2O4、Ni2CoO4和CoTa2O6,分布在外层的CoTa2O6抑制基体中元素Al向外扩散,形成内层氧化物Al2O,.在氧化期间,合金内部生成了内氮化物AlN,且在合金内部AlN与Al2O3成规律性分布,与外氧化膜相邻的为元素Al的内氧化物Al2O3区域,远离外氧化膜的基体内部为元素Al的内氮化物AlN区域,随氧化温度升高,内氧化区和内氮化区的深度增加,内氧化物和内氮化物的尺寸增大.
关键词:
金属材料
,
镍基合金
,
恒温氧化
,
动力学曲线
,
内氧化
,
内氮化
杨晓红
,
孙特
,
肖鹏
,
梁淑华
稀有金属材料与工程
以粒度6和300 nm的高纯钨粉级配后与TiH2粉混匀,经冷等静压压制后采用液相烧结制备W-10Ti合金.通过测试合金致密度,利用XRD,SEM及TEM等测试手段,研究了不同钨粉粒度对W-10Ti合金显微组织和相组成的影响.结果表明:全部用6μm钨粉时,制备的W-10Ti合金致密度仅为85％；但组织中W和Ti分布比较均匀,形成相结构相对单一的富W固溶体.全部用300 nm钨粉时,合金致密度可达到97％以上,但组织中有较多的富Ti固溶体.采取纳米与微米W粉级配时,级配比越小,W-10Ti合金中富W固溶体含量越多,但致密度越低.级配比为1∶2时,致密度可达到95％,且形成相对单一的富W固溶体相.
关键词:
W-10Ti合金
,
液相烧结
,
级配比
,
致密度
,
富W固溶体
赵紫盈
,
刘金旭
,
张鸿雁
,
郭文启
,
李树奎
稀有金属
利用W颗粒表面化学镀Ni结合SPS的方法,制备了低W-W连接度65W-25Cu-10Ni合金,并开展了其准静态力学性能研究.结果表明,制得的Ni包W复合粉中,Ni包覆层分布均匀且与W结合良好;以Ni包W复合粉和Cu粉为原料制备的65W-25Cu-10Ni合金的组织均匀且致密.在准静态压缩加载条件下,与65W-35Cu合金相比,65W-25Cu-10Ni合金的强度及塑性均大幅度提高;在准静态拉伸加载条件下,与65W-35Cu合金相比,65W-25Cu-10Ni合金的强度较高,塑性没有明显提高.机理分析表明,与65W-35Cu合金相比,65W-25Cu-10Ni合金中W-W连接度较低,粘结相由Cu相转变为Cu0.81Ni0.19固溶体,且w与粘结相之间形成了冶金结合,以上3个因素共同导致65W-25Cu-10Ni合金强度的提高;此外,W-W连接度的降低以及W-粘结相界面结合强度的提高是65 W-25Cu-10Ni合金在准静态压缩加载条件下塑性提高的原因.
关键词:
65W-25Cu-10Ni合金
,
准静态力学性能
,
化学镀Ni
,
SPS
,
W-W连接度
Oxidation of Metals
The oxidation of four Ni-10Cr-ySi-4Al alloys has been studied in 1 atm O(2) at 900 and 1000 degrees C to examine the effects of various Si additions on the behavior of the ternary alloy Ni-10Cr-4Al, which during an initial stage formed external NiO scales associated with an internal oxidation of Cr + Al, later replaced by the growth of a chromia layer at the base of the scale plus an internal oxidation of Al. The addition of 2 at.% Si was able to prevent the oxidation of nickel already from the start of the test, but was insufficient to form external alumina scales at 1000 degrees C, while at 900 degrees C alumina formed only over a fraction of the alloy surface. At 1000 degrees C the addition of 4 at.% Si produced external chromia scales plus a region of internal oxidation of Al and Si, a scaling mode which formed over a fraction of the alloy surface in combination with alumina scales also by oxidation at 900 degrees C. Conversely, the presence of about 6 at.% Si produced external alumina scales over the whole sample surface at 900 degrees C, but only over about 60% of the alloy surface at 1000 degrees C. The changes in the oxidation modes of the ternary Ni-10Cr-4Al alloy produced by Si additions have been interpreted by extending to these quaternary alloys the mechanism of the third-element effect based on the attainment of the critical volume fraction of internal oxides needed for the transition to the external oxidation of the most-reactive-alloy component, already proposed for ternary alloys.
关键词:
Ni-Cr-Si-Al alloys;oxidation;third-element effect;intermediate oxidant pressures;most-reactive components;1200 degrees;c;internal oxidation;external oxidation;transition;at.percent;silicon;x=0
Corrosion Science
The oxidation in 1 atm of pure oxygen of Ni-Cr-Al alloys with a constant aluminum content of 7 at.% and containing 5, 10 and 15 at.% Cr was studied at 900 and 1000 degrees C and compared to the behavior of the corresponding binary Ni Al alloy (Ni-7Al). A dense external scale of NiO overlying a zone of internal oxide precipitates formed on Ni-7Al and Ni-5Cr-7Al at both temperatures. Conversely, an external Al2O3 layer formed on Ni-10Cr-7Al at both temperatures and on Ni-15Cr-7Al at 900 degrees C, while the scales grown initially on Ni-15Cr-7Al at 1000 degrees C were more complex, but eventually developed an innermost protective alumina layer. Thus, the addition of sufficient chromium levels to Ni-7Al produced a classical third-element effect, inducing the transition between internal and external oxidation of aluminum. This effect is interpreted on the basis of an extension to ternary alloys of a criterion first proposed by Wagner for the transition between internal and external oxidation of the most reactive component in binary alloys. (c) 2006 Elsevier Ltd. All rights reserved.
关键词:
ternary alloys;Ni-Cr-Al;oxidation;third-element effect;cr-al alloys;most-reactive component;high oxidant pressures;internal;oxidation;ternary alloys;external oxidation;high-temperature;protective scales;aluminum alloys;binary-alloys
