共查询到18条相似文献,搜索用时 202 毫秒
1.
2.
无铅微焊点界面断裂行为的尺寸效应 总被引:2,自引:0,他引:2
采用有限元模拟和试验方法研究不同尺寸的"铜引线/钎料/铜引线"对接结构微焊点在准静态微拉伸载荷下的断裂行为,以及电迁移与热时效作用对其断裂性能的影响.结果表明,随着微焊点高度的减小,焊点中界面裂纹扩展驱动力逐渐减小,抗断裂性能有所提高;界面裂纹尖端剪切型裂纹扩展驱动力KⅡ值明显高于张开型裂纹扩展驱动力KⅠ值;Sn-Ag-Cu无铅钎料微焊点中界面裂纹的应力强度因子KⅡ和KⅠ远低于Sn-Pb钎料微焊点,其抗断裂能力要明显优于后者.模拟结果还表明,电迁移极性效应导致的金属间化合物增厚对微焊点断裂性能影响不大,而焊点边缘微空洞的横向薄饼状扩展导致界面应力集中系数显著上升,最大Von Mises等效应力点位于金属间化合物/铜界面处;微焊点在热时效过程中两侧界面金属间化合物层厚度的增加使界面裂纹尖端的应力水平近似呈指数函数衰减. 相似文献
3.
《机械工程学报》2017,(2)
借助纳米压痕试验方法,对Cu/SAC305/Cu,Cu/SAC0705/Cu和Cu/SAC0705BiNi/Cu微焊点体钎料在不同最大载荷下的压入蠕变性能进行比较,并分析和讨论Bi、Ni元素的添加对低银Cu/SAC0705/Cu微焊点体钎料蠕变性能的影响。试验采用一次加载-卸载方式,加载时最大载荷分别为20mN、30mN、40mN和50mN,保载时间均为180s。采用FEISIRION扫描电子显微镜对微焊点体钎料在不同最大载荷下的压痕形貌进行观察。结果表明:在相同最大载荷和保载时间条件下,3种微焊点中Cu/SAC0705BiNi/Cu的蠕变深度和压痕尺寸均小于Cu/SAC305/Cu和Cu/SAC0705/Cu。在4种不同最大载荷下,与Cu/SAC0705/Cu微焊点体钎料相比,Cu/SAC0705BiNi/Cu微焊点体钎料的压入蠕变率分别降低了11.883%、16.059%、8.8157%和12.891%。Bi、Ni元素的添加,使Cu/SAC0705/Cu微焊点体钎料的蠕变应力指数提高了32.175%,有效提高了低银Cu/SAC0705/Cu微焊点体钎料的抗蠕变性能。 相似文献
4.
5.
BGA结构无铅微焊点的低周疲劳行为研究 总被引:2,自引:0,他引:2
基于塑性应变能密度概念提出微焊点低周疲劳裂纹萌生、扩展和寿命预测模型,阐明其与连续介质损伤力学的联系,评估应力三轴度对预测模型的影响,并通过试验和数值计算相结合的方法确定出微米尺度球栅阵列(Ball grid array,BGA)结构单颗Sn3.0Ag0.5Cu无铅焊点(高度为500~100 μm,焊盘直径为480 μm)疲劳裂纹萌生和扩展模型中的相关常数。研究结果表明,疲劳裂纹萌生和扩展循环数与每个循环所产生的塑性应变能密度均呈幂函数关系;应力三轴度会影响疲劳裂纹扩展速率,并最终影响焊点的疲劳寿命;应力三轴度与加载方式有关,拉伸载荷下焊点的应力应变行为受异种材料界面和封装结构力学约束作用的影响,应力三轴度随焊点高度降低而明显升高;而剪切载荷作用下焊点中的力学约束十分有限,焊点高度变化对应力三轴度的影响非常小;测得的高度为100 μm焊点的疲劳裂纹扩展相关常数可以很好地用于预测其他不同高度焊点的疲劳寿命,表明所提出的预测模型可以有效地减小由几何结构和体积变化造成的塑性应变能集中现象对焊点疲劳寿命的影响。 相似文献
6.
7.
研究了铝合金AA5754点焊拉剪接头的疲劳性能,获得了不同厚度试件的载荷寿命曲线。研究了铝合金焊点的疲劳失效模式,讨论了焊点疲劳裂纹的扩展形式,并测量了裂纹扩展路径与点焊熔核界面之间的角度。分析了点焊拉剪试件在同时承受I型和II型载荷时,疲劳裂纹的扩展方向,并与测量值进行了比较。利用疲劳破坏后沿铝板厚度方向的实际裂纹长度修正了裂纹尖端的局部应力强度因子,提出了评价焊点寿命的疲劳参量K(i),并对试验数据进行了分析比较。结果证明K(i)可以有效关联试件尺寸效应和焊点疲劳寿命,能够用于预测焊点疲劳寿命。 相似文献
8.
研究了铝合金AA5754和AA6111-T4焊点的疲劳性能,获得了不同厚度及试件类型的焊点疲劳数据;研究了试件类型不同时焊点的疲劳失效模式,讨论了焊点疲劳裂纹的扩展形式;分析了铝合金焊点疲劳寿命的影响因素。结果表明:焊点疲劳失效模式主要有两种,分别是母材“眉状”裂纹断裂和焊点熔核界面断裂;母材对焊点疲劳寿命影响不大;循环载荷比对焊点寿命有一定的影响,增大载荷比导致焊点疲劳寿命略有下降;试件类型对焊点寿命有很大的影响,应在设计中避免焊点承受剥离载荷。 相似文献
9.
焊接结构的疲劳裂纹常常萌生于焊趾局部。在复杂的冶金物理作用下,焊趾局部的微观晶粒尺寸及其分布形态呈现明显差异性。为了探究晶粒分布形态对焊趾短裂纹疲劳行为的影响,针对十字焊接接头试件,对焊趾局部的不同区域进行了金相检验,获得粗晶区和细晶区的平均晶粒尺寸,构建了虑及晶粒分布形态的二维代表性体积单元(RVE)模型,基于FIP参量和McDowell模型实现了不同晶粒分布形态对焊趾短裂纹的成核与疲劳扩展行为的模拟,结果表明,微观晶粒尺寸和取向是焊趾短裂纹成核行为的重要影响因素;晶粒分布形态对短裂纹的早期行为影响较小,但在裂纹扩展至某个阈值长度之后,影响逐渐显著;一般情况下,细晶到粗晶的过渡方式可降低短裂纹的扩展速率。 相似文献
10.
选取焊盘长度、焊盘宽度、钢网厚度和间隙高度为四个关键因素,采用水平正交表L25(56)设计25种不同参数水平组合的底部引线塑料封装(bottom leaded plastic,BLP)器件焊点,建立25种焊点的形态预测模型和有限元分析模型;对热循环加载条件下BLP焊点进行非线性有限元分析,计算25种不同焊点形态的BLP焊点热疲劳寿命;基于热疲劳寿命计算结果进行极差分析.结果表明,四个因素对BLP焊点热疲劳寿命影响由大到小的顺序依次是焊盘宽度、焊盘长度、间隙高度和钢网厚度;可靠性最高的BLP焊点工艺参数水平组合为焊盘长度1.1 mm、焊盘宽度0.65 mm、钢网厚度0.15 mm和间隙高度0.09 mm. 相似文献
11.
R.S. Chen S.C. Tseng C.S. Wan 《The International Journal of Advanced Manufacturing Technology》2006,27(7-8):677-687
Among the PBGA (plastic ball grid array) packages, a 72-I/O OMPAC (overmolded effect array carrier) package is studied during
thermal cycling. The ANSYS software is applied to analyze the effects of some factors on the solder joint for the fatigue
life due to elastoplastic deformation of the electronic package; those factors are solder structure, shape, and pitch. The
result shows that the maximum equivalent plastic strain range occurs at two interfaces, one is between the solder joint and
the substrate, another one is between the solder joint and the printed circuit board. Moreover, the solder shape is determined
by the solder height and the pad diameter under a fixed value of solder volume. It is found that the convex-shaped solder
with larger height and smaller pitch has smaller maximum equivalent plastic strain range, which leads to the longer fatigue
life. In addition, there are two kinds of solder structure: pure solder joint and copper core solder joint. In the copper
core solder joint, the eutectic part becomes so small that a larger strain is induced. Therefore, the pure solder joint has
smaller maximum equivalent plastic strain range and longer fatigue life than the copper core solder joint. 相似文献
12.
Ouk Sub Lee Yeon Chang Park Dong Hyeok Kim 《Journal of Mechanical Science and Technology》2008,22(4):683-688
One of major reasons for the failure of solder joints is thermal fatigue. Also, the failure of solder joints under thermal
fatigue loading is influenced by varying boundary conditions such as the material of the solder joint, the materials of substrates(related
to the difference in CTE), the height of solder, the distance of the solder joint from the neutral point (DNP), the temperature
variation and the dwell time. In this paper, first, the experimental results obtained from thermal fatigue test are compared
to the outcomes from theoretical thermal fatigue life equations. Second, the effects of varying boundary conditions on the
failure probability of the solder joint are studied by using probabilistic methods such as the first order reliability method
(FORM) and Monte Carlo simulation (MCS). 相似文献
13.
PBGA焊点的热疲劳寿命分析 总被引:6,自引:0,他引:6
采用焊点阵列数学分析的方法得到阵列在热循环载荷作用下,由于元件、焊点及基板的热膨胀系数不匹配所产生的阵列对关键点焊点的热位移影响。然后利用焊点盛开有软件得到焊点的形态,通过编制相关转换程序进行关键焊点的非一有限元分析,从而得到关键焊一内的最大变值,利用低周热疲劳寿命预测公式得到焊点的热疲劳寿命。 相似文献
14.
15.
针对应力比对疲劳裂纹扩展及门槛值的影响,依据裂纹闭合与裂纹扩展驱动力机制的统一思想,阐述了Zhu-Xuan模型与Kwofie-Zhu模型的建立过程,并基于25Cr2Ni2MoV转子钢焊接接头的疲劳裂纹扩展试验数据对模型进行验证。结果表明,两种模型在近门槛值区和Paris区均有良好的预测效果,其中Zhu-Xuan模型形式简单,对CrMoV钢具有普适性,预测门槛值的误差在10%以内,而Kwofie-Zhu模型预测结果更准确,但应用过程涉及参数求解,过程较复杂。研究认为,裂纹闭合与扩展驱动力机制的统一模型描述疲劳裂纹扩展行为的应力比相关性是合理可行的,且具有较好精度。 相似文献
16.
Young-Eui Shin Jun Hwan Lee Young-Wook Koh Chong-Won Lee Jun Ho Yun Seung-Boo Jung 《Journal of Mechanical Science and Technology》2002,16(7):919-926
In this study, the numerical prediction of the thermal fatigue life of a μBGA (Micro Ball Grid Array) solder joint was focused.
Numerical method was performed using the three-dimensional finite element analysis for various solder alloys such as Sn-37%Pb,
Sn-3.5%Ag, Sn-3.5%Ag0.7%Cu and Sn-3.5%Ag-3%In-0.5%Bi during a given thermal cycling. Strain values obtained by the result
of mechanical fatigue tests for solder alloys, were used to predict the solder joint fatigue life using the Coffin-Manson
equation. The numerical results showed that Sn-3.5%Ag with the 50-degree ball shape geometry had the longest thermal fatigue
life in low cycle fatigue. A practical correlation for the prediction of the thermal fatigue life was also suggested by using
the dimensionless variable γ. Additionally Sn-3.5Ag-O.75Cu and Sn-2.0Ag-0.5Cu-2.0Bi were applied to 6X8μBGA obtained from
the 63Sn-37Pb Solder. This 6X8μBGA were tested at different aging conditions at 130°C, 150°C, 170°C for 300, 600 and 900 hours.
Thickness of the intermetallic compound layer was measured for each condition and the activation energy for their growth was
computed. The fracture surfaces were analyzed using SEM (Scanning Electron Microscope) with EDS (Energy Dispersive Spectroscopy). 相似文献
17.
焊后热处理对30CrMnSiNi2A钢电子束焊接件疲劳行为的影响 总被引:2,自引:0,他引:2
电子束局部热处理是一种新型的热处理方式,探讨其对电子束焊接接头组织和疲劳性能的影响规律具有十分重要的实际意义。文中采用CT(紧凑拉伸)试样,对30CrMnSiNi2A钢电子束焊接后焊态、焊后炉内整体热处理和电子束局部热处理三种焊接接头焊缝与母材的疲劳裂纹扩展速率进行试验研究;并测定上述两个部位的门槛值。结合金相组织分析,讨论焊后热处理对接头疲劳行为的影响。试验结果表明,电子束局部热处理和整体热处理都能够在一定程度上改善焊接接头的组织和近门槛值处抗疲劳裂纹扩展的能力。由于电子束局部热处理具有方便、省时、节省能源和提高生产率的优点,因而具有较大的应用潜力和研究价值。 相似文献