徐慧
,
王春青
,
杭春进
金属学报
金丝球焊是电子工业中应用最广泛的引线键合技术，但随着高密度封装的发展，铜丝球焊日益引起人们的关注。本文采用热压超声丝球键合的方法，将直径50μmCu引线键合到Al-1%Si-0.5%Cu金属化焊盘。对焊点在不同温度下进行老化，通过SEM、EDX和Micro-XRD观察和分析IMC生长情况。结果表明：Cu/Al IMC的生长取决于老化温度和时间，在老化温度一定时，IMC厚度随与老化时间的关系符合抛物线法则，IMC生长对于老化温度比老化时间更加敏感；Cu/Al IMC生长的激活能为85Kcal/mol；老化后Cu/Al IMC为层状分布，主要的IMC为CuAl2和Cu9Al4。
关键词:
铜丝球键合
,
IMC
,
Aging
,
Micro-XRD
A. Momeni K. Dehghani
材料科学技术（英文）
In this research, aging treatments at temperatures of 800 and 900°C for different aging time of 5{60 min were conducted on solution treated as well as hot worked samples of 2205 dual phase stainless steel. The effect of aging treatment on precipitation of intermetallic phases was investigated in undeformed specimens and those subjected to hot deformation with different strain rates of 0.001−1 s−1. It was found that σ precipitation increased by hot working. It was also concluded that the volume fraction of phase increased with deformation temperature and decreased with strain rate. The precipitation of intermetallic phases (i.e. σ and χ) was analyzed by an Avrami-type kinetics equation of %(σ+χ)=A(1-exp(-ktn)) and the values of n and ln k were estimated for different thermomechanical regimes. The values of n were assessed to increase from 0.4 to 1 with strain rate in the studied range. Otherwise, It was also understood that ln k decreased with strain rate. Microstructural observations by means of optical microscopy and scanning electron microscopy showed that σ particles mostly nucleated at the ferrite-austenite interfaces. But no sign of Â-phase could be seen. This fortified the idea of certain literature that Â-phase always forms at early stages of aging and consumes through the precipitation of σ.
关键词:
Duplex stainless steel
,
Hot Working
,
Sigma Phase
,
Secondary Phase
魏小荣
,
赵世金
上海金属
采用分子动力学模拟了Fe-1.95％ Cu-1.95％ Ni合金在823 K下的时效过程.结果表明:在Fe-Cu-Ni合金中,Cu和Ni之间存在一种相互促进扩散相互促进析出的协同作用；Cu、Ni的扩散过程都存在三个扩散速率不同的阶段,分别为自由迁移形成团簇的过程,溶质团簇的不断形成过程和团簇的长大过程.
关键词:
Fe-1.95％Cu-1.95％Ni合金
,
分子动力学模拟
,
时效
,
扩散
A. Momeni K. Dehghani
材料科学技术（英文）
In this research, aging treatments at temperatures of 800 and 900°C for different aging time of 5{60 min were conducted on solution treated as well as hot worked samples of 2205 dual phase stainless steel. The effect of aging treatment on precipitation of intermetallic phases was investigated in undeformed specimens and those subjected to hot deformation with different strain rates of 0.001−1 s−1. It was found that σ precipitation increased by hot working. It was also concluded that the volume fraction of phase increased with deformation temperature and decreased with strain rate. The precipitation of intermetallic phases (i.e. σ and χ) was analyzed by an Avrami-type kinetics equation of %(σ+χ)=A(1-exp(-ktn)) and the values of n and ln k were estimated for different thermomechanical regimes. The values of n were assessed to increase from 0.4 to 1 with strain rate in the studied range. Otherwise, It was also understood that ln k decreased with strain rate. Microstructural observations by means of optical microscopy and scanning electron microscopy showed that σ particles mostly nucleated at the ferrite-austenite interfaces. But no sign of Â-phase could be seen. This fortified the idea of certain literature that Â-phase always forms at early stages of aging and consumes through the precipitation of σ.
关键词:
Duplex stainless steel
,
Hot Working
,
Sigma Phase
,
Secondary Phase
Fuquan LI
,
Chunqing WANG
,
Yanhong TIAN
材料科学技术（英文）
The interfacial phenomena of the Sn-Pb solder droplet on Au/Ni/Cu pad are investigated. A continuous AuSn2 and needle-like AuSn4 are formed at the interface after the liquid state reaction (soldering). The interfacial reaction between the solder and Au layer continues during solid state aging with AuSn4 breaking off from the interface and felling into the solder. The kinetics of Au layer dissolution and diffusion into the solder during soldering and aging is analyzed to elucidate intermetallic formation mechanism at the solder/Au pad interface. The concentration of Au near the solder/pad interface is identified to increase and reach the solubility limit during the period of liquid state reaction. During solid state reaction, the thickening of Au-Sn compound is mainly controlled by element diffusion.
关键词:
Sn-Pb solder droplet
,
老化
,
溶解
,
钎料熔滴
左永权
,
韩丽娜
,
鲍卫仁
,
常丽萍
,
王建成
催化学报
doi:10.1016/S1872-2067(11)60517-2
采用X射线衍射、扫描电镜、原子吸收、程序升温还原、X射线吸收近边吸收谱、X射线光电子能谱、氮吸附等手段对水热合成(HS)、等体积浸渍(PVI)与离子交换(IE)法制备的CuSAPO-34样品进行了表征,并评价了老化前后催化剂上C3H6-SCR与NH3-SCR脱除模拟柴油车尾气中NOx的反应活性.结果表明,IE法制得的催化剂活性最高,尤其在C3H6-SCR低温阶段；PVI法制得的催化剂活性最差.制备方法影响CuSAPO-34催化剂的比表面积、孔径分布和活性组分价态从而改变其催化活性.各催化剂均存在Cu+和Cu2+,但比例明显不同.HS样品以Cu2+为主,另两种样品则含较多的Cu+.老化不仅部分破坏了分子筛的形貌、降低了分子筛的比表面积,尤其是表面Cu含量,而且有部分Cu生成了CuSO4,使得老化后催化剂的脱硝活性降低.PVI法制得的催化剂老化后活性下降幅度最小,表明该分子筛抗老化能力较强.
关键词:
CuSAPO-34
,
水热合成
,
离子交换
,
等体积浸渍
,
选择性催化还原
,
老化
Xianglong MENG
,
Wei CAI
,
K.T.Lau
,
L.M.Zhou
,
Liancheng ZHAO
,
null
,
null
材料科学技术（英文）
The use of Ni-rich TiNiHf alloys as high temperature shape memory alloys (SMAs) through aging has been presented. For Ni-rich Ti80-xNixHf20 alloys, their phase transformation temperatures are averagely increased more than 100 K by aging at 823 K for 2 h. Especially for the alloys with Ni-content of 50.4 at. pct and 50.6 at. pct, their martensitic transformation start temperatures (Ms) are more than 473 K after aging. TEM observation confirmed that some fine particles precipitate from the matrix during aging. The aged Ni-rich TiNiHf SMAs show the better thermal stability of phase transformation temperatures than the solutiontreated TiNiHf alloys. The fine particles precipitated during aging should be responsible for the increase of phase transformation temperatures and its high stability.
关键词:
TiNiHf alloy
,
null
,
null
,
null
H. Jafari
金属学报(英文版)
doi:10.1016/S1006-7191(08)60115-5
Due to their high specifc strength and low density, magnesium alloys are widely used in many weight-saving applications. This research is aimed at investigating the microstructure and hardness of commercial AZ63 alloy specimens subjected to two diferent thermomechanical treatments (TMTs). For the first TMT, after solution treated at the temperature of 380 ℃ for 20 h, AZ63 alloy specimens were 5% cold worked by rolling process followed by ageing at the temperatures of 150 ℃ and 250 ℃ for 3, 9 and 25 h. In the second TMT, the specimens were solution treated at the temperature of 380 ℃ for 20 h, underwent 2% cold worked and quenched in water of 0 ℃. Half of the specimens were then 2% cold worked whilst the rest were rolled to 8% cold worked. All the specimens were then aged at the temperatures of 150 ℃ and 250 ℃ for 3, 9 and 25 h. Optical microscope was used to analyze the microstructures of the specimens. Hardness test was too conducted to measure the effect of the treatments on the specimens. Results show that two-step aging enhances the hardness of the specimens due to the distribution of the Beta-phase (Mg17Al12) in the alloy matrix. The results also reveal that, the best hardness from the first TMT was produced by specimen that was pre-aged at 150 ℃ whereas, in the second TMT, aging at 250 ℃ exhibited the best hardness values.
关键词:
Thermomechanical treatment
,
Magnesium
,
Cold work
,
Aging
,
AZ63
Zheng LIU
,
Ligang WANG
,
Lai WANG
材料科学技术（英文）
The microstructures, the changing rule of carbon-enriched zone, the diffusion behaviors of elements C and Cr, and the carbide type of 0Cr6Mn13Ni10MoTi/1Cr5Mo dissimilar welded joints after aging at 500℃ for various times and after long-term service in technical practice were investigated by using the optical microscopy, electron probe microanalysis, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results show that in aging 0Cr6Mn13Ni10MoTi/1Cr5Mo dissimilar welded joints, the main carbides are M3C and a few carbides are M7C3 and M23C6. The M3C carbide decomposition and dissolution with increasing aging time or aging temperature and the anti-diffusion of C and Cr cause the decrease and disappearance of the carbon-enriched zone. The results are different from those of the A302/1Cr5Mo dissimilar welded joints in previous studies.
关键词:
Dissimilar welded joint
,
null
,
null
,
null
