Shear strength and aging characteristics of 63Sn−37Pb solder bumps with various solder ball and pad sizes

The shear strength and aging characteristics of 63Sn–37Pb solder bumps were characterized with variation in solder ball and UBM pad sizes. The shear strength increased with shorter effective crack size,a _effs which was determined with the solder ball and pad sizes. The shear strength of the solder bumps on Au/Ni/Cu and Ni/Cu did not change significantly with reflow time. Substantial decrease in the shear strength occurred for the solder bumps formed on Au/Ni/Cu with aging treatment, and the shear strength after aging was also related to the bump shape which was determined with the solder ball and pad sizes.     

Effect of ultrasonic power and bonding force on the bonding strength of copper ball bonds

Copper wire, serving as a cost-saving alternative to gold wire, has been used in many high-end thermosonic ball bonding applications. In this paper, the bond shear force, bond shear strength, and the ball bond diameter are adopted to evaluate the bonding quality. It is concluded that the ef/~cient ultrasonic power is needed to soften the ball to form the copper bonds with high bonding strength. However, excessive ultrasonic power would serve as a fatigue loading to weaken the bonding. Excessive or less bonding force would cause cratering in the silicon.     

Textures in high purity aluminum foils and AA3004 sheets

1　INTRODUCTIONWithincreasingdemandsofhighmaterials properties ,thetexturesinAlandAlalloysplaymoreandmoreimportantrole .Highpurityaluminumfoilsneedverystrongcubetexture ,whichwillfavorthe“channeletching”effectforhighvoltageelectrolyticcapacitors ,andAA30 0 4aluminumalloysheetsneedcertaincubetexturetosuppressthe 4 5°earingbehav iorresultingfromstrongrollingtexturecompo nents[1] .InAlandAlalloys ,heavycoldrollingwillresultinstrongβ fibertexturescomposedofthewellknownCu ({ 112 }〈111〉…     

基于人工智能的钛合金热变形工艺参数优化

在深入分析热变形工艺参数对Ti-15-3合金显微组织及成形载荷的影响的基础上,以变形温度、变形程度和变形速率等热变形工艺参数作为设计变量,以显微组织和成形力的最佳综合为目标,建立了该合金热塑性成形工艺参数的多目标优化数学模型。以显微组织参数和成形力的人工神经网络预测模型作为优化算法的知识源,将人工神经网络与修正的遗传算法相结合,对Ti-15-3合金的热塑性成形工艺参数进行优化。结果表明,提出的修正的遗传算法是有效的,采用将其与人工神经网络相结合的方法对钛合金的热塑性成形工艺参数进行优化是可行的。     

STRAIN INDUCED STRUCTURAL TRANSITION OF INTERFACES AND TWINS IN A HOT－DEFORMED DUAL－PHASE TIAL ALLOY

ＳＴＲＡＩＮＩＮＤＵＣＥＤＳＴＲＵＣＴＵＲＡＬＴＲＡＮＳＩＴＩＯＮＯＦＩＮＴＥＲＦＡＣＥＳＡＮＤＴＷＩＮＳＩＮＡＨＯＴ－ＤＥＦＯＲＭＥＤＤＵＡＬ－ＰＨＡＳＥＴＩＡＬＡＬＬＯＹＣＨＥＮＧｕｏＦｉａｎｇ；ＷＡＮＧＪｉｎｇｕｏ；ＺＨＡＮＧＬｉｃｈｕｎａｎｄ...     

剪切变形方向特征对高纯铝箔轧制织构的影响

运用取向分布函数(ODF)研究了每个轧制道次的剪切变形特征对高纯铝箔轧制织构的影响.提出用中性角的相对大小来量化轧制剪切变形作用方向改变的位置,运用Taylor晶体塑性变形理论模拟计算了中性角的相对大小对轧制织构演变的影响.实测与模拟的轧制织构特征表明:中性角靠近轧制变形区的中心位置有利于形成{001}<110>剪切织构,从而证实了除剪切变形的程度外,剪切变形方向改变的位置也是影响高纯铝箔轧制织构的重要因素.     

轴类零件校直工艺广义预测多步算法研究

本文基于行程控制的轴类零件校直工艺公式 ,构建了模拟轴类零件校直工艺过程的广义预测控制模型 ,应用广义预测算法 ,实现了对轴类零件弹塑性非线性残余变形的均匀控制 ,实验研究表明 ,该方法能满足精密校直要求 ,并且随着控制步长的增多 ,控制效果显著。     

Effects of Austempering after Hot Deformation on the Mechanical Properties of Hot Rolled Si-Mn TRIP Steel Sheets

Excellent mechanical properties are obtained by austempering after hot deformation without subsequent heat treatment in the present Si-Mn TRIP steel sheets. Isothermal holding time after finishing rolling has affected the mechanical properties of this steel. The results show that the sample exhibits a good combination of ultimate tensile strength and total elongation when it is held at the bainite transformation temperature after hot deformation. The stability of retained austenite increases with an increase of isothermal holding time, and a further increase in the holding duration results in a decrease of it. The tensile strength, total elongation and strength ductility reach the maximum values (774MPa, 33% and 25542MPa% respectively) for this sort of hot rolled Si-Mn TRIP steel using the optimal technology.     

3003铝合金热变形流变应力特征

采用Gleeble-1500热模拟机进行圆柱体压缩实验．研究了3003铝合金在变形温度为300～500℃、应变速率为0．01～10s^-1、真应变为0～0．8条件下的流变应力特征。结果表明．流变应力随温度升高而降低，随应变速率的提高而增大；在应变速率小于10s^-1。时，3003铝合金首先出现加工硬化，流变应力达到峰值后单调下降，趋于平稳，表现出动态回复的特征；而在应变速率为10s^-1、变形温度在350℃以上时，合金发生了局部动态再结晶；可用Zener-Hollomon参数的双曲正弦形式来描述3003铝合金热压缩变形时的流变应力行为。     

含Ti微合金钢动态再结晶行为及模型研究

采用Gleeble 3800热力模拟实验机,研究了一种Ti微合金钢在850～1 150℃、0.1和1.0 s-1条件下的变形奥氏体的动态再结晶行为及再结晶后奥氏体晶粒尺寸的演化规律。结果表明:形变激活能与变形条件相关,随着应变速率的增加而增加;Avrami指数m同样与变形条件有关;对实验数据进行回归分析后建立的Ti微合金钢动态再结晶的特征应变、特征应力、动力学以及稳定状态晶粒尺寸的数学模型精度较高。