Sr含量对Al-Si合金显微组织和热导率的影响

以纯铝、Al-20Si和Al-10Sr中间合金为原料,Sr为变质剂(含量为0.01%、0.02%、0.04%和0.06%,质量分数),制备了Al-7Si-xSr、Al-12Si-xSr和Al-20Si-xSr合金,研究了Sr含量对Al-Si合金相变储热材料显微组织及热导率的影响。利用Hot Disk热常数分析仪测量合金的热导率,通过扫描电镜观察及分析合金的显微组织。结果表明:在Al-Si合金中添加变质元素Sr会影响合金的热导率,Al-7Si-0.04Sr合金热导率较Al-7Si合金增加了73.47 W·m^(-1)·K^(-1),Al-20Si-0.04Sr合金的热导率较Al-20Si合金增加了24.09 W·m^(-1)·K^(-1),Al-12Si-0.04Sr合金的热导率较Al-12Si合金增加了17.79 W·m^(-1)·K^(-1)。铝硅合金热导率的增长主要与α(Al)、共晶硅和初晶硅的形貌有关。经过Sr变质之后,Al-7Si合金中共晶Si立体形貌均由片层状转变为珊瑚状,Al-12Si和Al-20Si合金中共晶Si立体形貌由片层状转变为枝条状;其中,Al-7Si合金中α(Al)尺寸明显减少、排列紧密,二次枝晶臂间距逐渐减小;Al-20Si合金中的初晶Si尺寸明显减小,其形貌由多角的大块状变为小块状;α(Al)形态的转变不仅能够为自由电子的传输提供快速通道,而且还会使得共晶Si的排列更加规则,减少自由电子发生散射的几率,对合金的热导率影响较大。共晶Si由片层状转变为珊瑚状或枝条状,增加电子的平均自由程,有利于电子的传输。Al-20Si合金的热导率与初晶Si的形态有着重要联系,大尺寸且形状完整的初晶Si会发生晶格振动,会提高合金的热导率。

Al-Si镀层22MnB5激光焊的熔池流动特性及元素分布

熔池流动行为对镀层元素在焊缝中的分布起决定性作用.采用建立激光焊熔池三维瞬态数值模型的方法,分析AlSi镀层22MnB5高强度钢激光焊的熔池流动行为及其对焊缝中Al元素分布的影响规律.在焊接试验中,根据能谱仪对焊接接头的扫描数据验证数值模型的可靠性.结合模拟结果与试验结果对激光焊熔池流动行为及焊缝Al元素分布规律进行研究.结果表明,根据激光焊热输入与功率密度阈值的不同,熔池形貌呈现无匙孔、未完全贯穿匙孔和完全贯穿匙孔3种特征,并存有不同的温度场、流场、流速和稳定性.无匙孔熔池由于流速分布均匀,涡流产生较少,稳定性最好.镀层Al元素在焊接接头上下焊趾区域易产生偏聚,较之上表面镀层,下表面镀层进入熔池后Al元素偏聚现象更明显.因此,上部Al元素均质化分布显著优于下部.

SiCp/Al-Si基复合材料界面结构调控及强化机制的研究进展

SiCp/Al-Si基复合材料具有高的比强度、比刚度、比模量,良好的导热、导电、耐磨性及尺寸稳定性等优点,作为结构功能性材料应用于空间工程、电子封装、交通运输和精密仪器等领域。其研究热点主要集中在界面结构调控、强化机制及性能调控等方面。在SiCp/Al-Si复合材料中存在着增强体与基体界面、析出相与基体界面、析出相与增强体界面,这些界面受各种因素影响,会出现多种界面反应和界面产物,界面结构和结合状态复杂而多样。基于此,本文综述了制备工艺、基体合金成分和SiCp表面改性等方面对SiCp/Al-Si基复合材料界面结构的影响及调控,并总结了影响其力学性能的因素及强化机制的研究现状,最后对复合材料未来的发展及研究方向进行了展望。

Si含量对Al-Si-Cu-Ni-Mg合金组织和性能的影响

采用搅拌铸造工艺制备不同Si含量合金,旨在揭示Si含量对Al-Si-Cu-Ni-Mg合金微观组织、力学性能和耐磨性的影响。结果表明,随着Si含量升高,合金中共晶Si长径比和平均长度先升高后降低,Si含量为16wt.%合金的长径比和平均长度最大,分别为8.8μm、24.1μm。经过520℃/6 h固溶+180℃/5 h时效处理后,共晶Si形貌由纤维状变为球状,初晶Si棱角钝化。合金中共晶Si长径比和平均长度均有明显降低,保持与铸态合金相同的变化趋势;Si含量为16wt.%合金的长径比和平均长度分别为3.5μm、12.4μm,初晶Si尺寸没有明显变化。随着Si含量的升高,铸态合金拉伸性能逐渐降低,宏观硬度逐渐上升。经过T6热处理后,合金的拉伸性能和宏观硬度有了明显提升,保持与铸态合金相同的变化趋势,随着Si含量的升高,合金磨损失重减少,耐磨性得到改善。Si含量为16wt.%的合金磨损失重最少,耐磨性最好;继续增加Si含量时,合金耐磨性降低。

固溶处理对铸造Al-Si合金相选择再结晶的影响

相选择再结晶在Al-Si合金中基于应变分配原理实现对软相进行再结晶、硬相进行回复从而球化硅相和细化铝相。相选择再结晶处理后合金呈现出高的加工硬化率和伸长率。固溶处理是实现铝合金强韧化的重要环节,与相选择再结晶互相影响。一方面,初始组织对相选择再结晶的应变分配有一定影响;另一方面铝合金固溶过程会影响析出强化作用。因此,本文探究铸造Al-7Si-0.65Mg合金固溶过程中共晶硅相的形貌对相选择再结晶的影响,结合时效析出实现合金的强韧化。结果表明,0.5 h短时间固溶处理可以保持相选择再结晶合金中清晰且不分散的共晶硅颗粒骨架状结构,同时增加基体中Si和Mg含量促进强化相Mg2Si析出,使合金屈服强度达到300 MPa,断后伸长率为9.5%,显著优于传统T6态。

Al-Si系铸造合金时效强化研究进展

Al-Si系铸造铝合金因其较好的铸造性能在汽车上广泛应用。为了进一步提高Al-Si铸造合金的强韧性,一般主要采用T6(固溶+时效)热处理的方式,而其中的时效处理十分关键。时效硬化过程异常复杂,合金成分、时效参数以及微量元素的引入都会对时效强化的效果产生影响。归纳总结了Al-Si-Cu、Al-Si-Mg以及Al-Si-Cu-Mg合金复杂的沉淀序列,分析了微量元素对时效析出行为的影响,最后指出了目前所面临的挑战以及未来的发展趋势。

Mn元素对Al-Si合金富铁相析出影响的热力学计算

本研究选取不同Mn元素含量的Al-7 wt%Si-0.2 wt%Fe铝液为研究对象,利用热力学软件定量计算了Mn元素添加量对铝液Scheil-Gulliver冷却凝固过程的析出相。结果表明:不同Mn元素含量的铝液冷却过程中相转变顺序有所不同,添加一定量的Mn元素可利于铝液凝固过程中析出Al3MnSi2相;添加Mn元素并不会大幅减少完全凝固后β-AlFeSi相的质量比,且不同Mn元素含量的铝合金中β-AlFeSi相质量比相差不超过1%,说明难以通过添加Mn元素来减少铝液完全凝固后的β-AlFeSi相质量比;铝液凝固末期,β-AlFeSi与Al3MnSi2发生共晶反应,Al3MnSi2对β-AlFeSi的形貌可能具有改性作用,是β-AlFeSi与Al3MnSi2的共晶相呈现出不规则形状的主要原因。

A comprehensive review of radiation effects on solder alloys and solder joints

In the realm of military and defence applications, exposure to radiation significantly challenges the performance and reliability of solder alloys and joints in electronic systems. This comprehensive review examines radiation-induced effects on solder alloys and solder joints in terms of microstructure and mechanical properties. In this paper, we evaluate the existing literature, including experimental studies and fundamental theory, to provide a comprehensive overview of the behavior of solder materials under radiation. A review of the literature highlights key mechanisms that contribute to radiation-induced changes in the microstructure, such as the formation of intermetallic compounds, grain growth,micro-voids and micro-cracks. Radiation is explored as a factor influencing solder alloy hardness,strength, fatigue and ductility. Moreover, the review addresses the challenges and limitations inherent in studying the effects of radiation on solder materials and offers recommendations for future research. It is crucial to understand radiation-induced effects on solder performance to design robust and radiationresistant electronic systems. A review of radiation effects on solder materials and their applications in electronics serves as a valuable resource for researchers, engineers, and practitioners in that field.

A review of extreme condition effects on solder joint reliability:Understanding failure mechanisms

Solder joint,crucial component in electronic systems,face significant challenges when exposed to extreme conditions during applications.The solder joint reliability involving microstructure and mechanical properties will be affected by extreme conditions.Understanding the behaviour of solder joints under extreme conditions is vital to determine the durability and reliability of solder joint.This review paper aims to comprehensively explore the underlying failure mechanism affecting solder joint reliability under extreme conditions.This study covers an in-depth analysis of effect extreme temperature,mechanical stress,and radiation conditions towards solder joint.Impact of each condition to the microstructure including solder matrix and intermetallic compound layer,and mechanical properties such as fatigue,shear strength,creep,and hardness was thoroughly discussed.The failure mechanisms were illustrated in graphical diagrams to ensure clarity and understanding.Furthermore,the paper highlighted mitigation strategies that enhancing solder joint reliability under challenging operating conditions.The findings offer valuable guidance for researchers,engineers,and practitioners involved in electronics,engineering,and related fields,fostering advancements in solder joint reliability and performance.

Preventing formation of intermetallic compounds in ultrasonic-assisted Sn soldering of Mg/Al alloys through pre-plating a Ni coating layer on the Mg substrate

Magnesium and aluminum alloys are widely used in various industries because of their excellent properties,and their reliable connection may increase application of materials.Intermetallic compounds(IMCs)affect the joint performance of Mg/Al.In this study,AZ31 Mg alloy with/without a nickel(Ni)coating layer and 6061 Al alloy were joined by ultrasonic-assisted soldering with Sn-3.0Ag-0.5Cu(SAC)filler.The effects of the Ni coating layer on the microstructure and mechanical properties of Mg/Al joints were systematically investigated.The Ni coating layer had a significant effect on formation of the Mg_(2)Sn IMC and the mechanical properties of Mg/Al joints.The blocky Mg_(2)Sn IMC formed in the Mg/SAC/Al joints without a Ni coating layer.The content of the Mg_(2)Sn IMC increased with increasing soldering temperature,but the joint strength decreased.The joint without a Ni coating layer fractured at the blocky Mg_(2)Sn IMC in the solder,and the maximum shear strength was 32.2 MPa.By pre-plating Ni on the Mg substrate,formation of the blocky Mg_(2)Sn IMC was inhibited in the soldering temperature range 240–280℃and the joint strength increased.However,when the soldering temperature increased to 310℃,the blocky Mg_(2)Sn IMC precipitated again in the solder.Transmission electron microscopy showed that some nano-sized Mg_(2)Sn IMC and the(Cu,Ni)_(6)Sn_(5)phase formed in the Mg(Ni)/SAC/Al joint soldered at 280℃,indicating that the Ni coating layer could no longer prevent diffusion of Mg into the solder when the soldering temperature was higher than 280℃.The maximum shear strength of the Mg(Ni)/SAC/Al joint was 58.2 MPa for a soldering temperature of 280℃,which was 80.7%higher than that of the Mg/SAC/Al joint,and the joint was broken at the Mg(Ni)/SAC interface.Pre-plating Ni is a feasible way to inhibit formation of IMCs when joining dissimilar metals.

Industrial Fusion Cascade Detection of Solder Joint

With the remarkable advancements in machine vision research and its ever-expanding applications,scholars have increasingly focused on harnessing various vision methodologies within the industrial realm.Specifically,detecting vehicle floor welding points poses unique challenges,including high operational costs and limited portability in practical settings.To address these challenges,this paper innovatively integrates template matching and the Faster RCNN algorithm,presenting an industrial fusion cascaded solder joint detection algorithm that seamlessly blends template matching with deep learning techniques.This algorithm meticulously weights and fuses the optimized features of both methodologies,enhancing the overall detection capabilities.Furthermore,it introduces an optimized multi-scale and multi-template matching approach,leveraging a diverse array of templates and image pyramid algorithms to bolster the accuracy and resilience of object detection.By integrating deep learning algorithms with this multi-scale and multi-template matching strategy,the cascaded target matching algorithm effectively accurately identifies solder joint types and positions.A comprehensive welding point dataset,labeled by experts specifically for vehicle detection,was constructed based on images from authentic industrial environments to validate the algorithm’s performance.Experiments demonstrate the algorithm’s compelling performance in industrial scenarios,outperforming the single-template matching algorithm by 21.3%,the multi-scale and multitemplate matching algorithm by 3.4%,the Faster RCNN algorithm by 19.7%,and the YOLOv9 algorithm by 17.3%in terms of solder joint detection accuracy.This optimized algorithm exhibits remarkable robustness and portability,ideally suited for detecting solder joints across diverse vehicle workpieces.Notably,this study’s dataset and feature fusion approach can be a valuable resource for other algorithms seeking to enhance their solder joint detection capabilities.This work thus not only presents a novel and effective solution for industrial solder joint detection but lays the groundwork for future advancements in this critical area.

Effect of Mo and ZrO_(2)nanoparticles addition on interfacial properties and shear strength of Sn58Bi/Cu solder joint

The influence of Mo and ZrO_(2)nanoparticles addition on the interfacial properties and shear strength of Sn58Bi solder joint was investigated.The interfacial microstructures of Sn58Bi/Cu,Sn58Bi+Mo/Cu and Sn58Bi+ZrO_(2)/Cu solder joints were analysed using a scanning electron microscope(SEM)coupled with energy dispersive X-ray(EDX)and the X-ray diffraction(XRD).Intermetallic compounds(IMCs)of MoSn_(2)are detected in the Sn58Bi+Mo/Cu solder joint,while SnZr,Zr_(5)Sn_(3),ZrCu and ZrSn_(2)are detected in Sn58Bi+ZrO_(2)/Cu solder joint.IMC layers for both composite solders comprise of Cu_(6)Sn_(5) and Cu_(3)Sn.The SEM images of these layers were used to measure the IMC layer’s thickness.The average IMC layer’s thickness is 1.4431μm for Sn58Bi+Mo/Cu and 0.9112μm for Sn58Bi+ZrO_(2)/Cu solder joints.Shear strength of the solder joints was investigated via the single shear lap test method.The average maximum load and shear stress of the Sn58Bi+Mo/Cu and Sn58Bi+ZrO_(2)/Cu solder joints are increased by 33%and 69%,respectively,as compared to those of the Sn58Bi/Cu solder joint.By comparing both composite solder joints,the latter prevails better as adding smaller sized ZrO_(2)nanoparticles improves the interfacial properties granting a stronger solder joint.

Effect of slow shot speed on externally solidified crystal,porosity and tensile property in a newly developed high-pressure die-cast Al-Si alloy

The effect of slow shot speed on externally solidified crystal(ESC),porosity and tensile property in a newly developed high-pressure die-cast Al-Si alloy was investigated by optical microscopy(OM),scanning electron microscopy(SEM)and laboratory computed tomography(CT).Results showed that the newly developed AlSi9MnMoV alloy exhibited improved mechanical properties when compared to the AlSi10MnMg alloy.The AlSi9MnMoV alloy,which was designed with trace multicomponent additions,displays a notable grain refining effect in comparison to the AlSi10MnMg alloy.Refining elements Ti,Zr,V,Nb,B promote heterogeneous nucleation and reduce the grain size of primaryα-Al.At a lower slow shot speed,the large ESCs are easier to form and gather,developing into the dendrite net and net-shrinkage.With an increase in slow shot speed,the size and number of ESCs and porosities significantly reduce.In addition,the distribution of ESCs is more dispersed and the net-shrinkage disappears.The tensile property is greatly improved by adopting a higher slow shot speed.The ultimate tensile strength is enhanced from 260.31 MPa to 290.31 MPa(increased by 11.52%),and the elongation is enhanced from 3.72%to 6.34%(increased by 70.52%).

Fe元素对Al-Si系再生铝合金组织性能的影响机理及其控制技术研究

Al-Si系铸造铝合金以其良好的铸造工艺性,高强度、耐磨和抗腐蚀等优点,被广泛应用于航空航天、船舶、交通、建筑车等具有轻量化需求的行业。同时Al-Si系铸造铝合金可多次循环利用,具有显著的经济优势。然而,铝合金在循环使用过程中的Fe元素杂质累积问题,影响了其品质和综合性能。综述了Fe含量对铝合金微观组织和性能的影响机理,并对添加元素中和法、熔体处理法以及热处理方法对Fe元素的控制进行了论述,对铝合金中Fe杂质元素的控制方法进行了展望。

Al-Si铸造合金的热处理强化与合金成分优化研究进展

概述了Al-Si铸造合金的热处理强化与合金成分优化进展情况,介绍了常用的热处理强化方法与合金强化元素。Al-Si铸造合金的强化研究对实现机动车轻量化、缓解日益严峻的能源和气候问题有重要意义。

Al-Si合金大型薄壁铸件抗变形工艺研究

使用Novacast软件模拟了铸件充型和凝固过程,采用3DP砂型打印机生产砂芯,在差压设备炉中进行熔炼浇注。由于舱体内部无凸台及环筋,在铸造及热处理过程中容易发生热变形,针对该问题修改工艺方案,在舱体外表面增加防变形环,防止铸件整体发生扭曲,对铸件增加防变形环状态进行模拟仿真,确保铸件内部质量符合要求,增加防变形工装后,内腔尺寸变形量控制在±0.5 mm,铸件尺寸得到保证,解决了该大型薄壁铝硅合金铸件铸造及热处理变形问题。

稀土Er对Al-Si-Cu钎料显微组织与性能的影响

为了研究微量稀土元素Er对Al-7Si-20Cu钎料合金性能的影响，进行了不同wE4对Al-7Si-20Cu合金熔化温度、润湿性能及力学性能的试验研究．结果表明，添加微量Er对Al-Si-Cu钎料合金的熔化温度无显著影响，但显著提高Al-Si-Cu钎料合金对被焊基体铝合金（LF21）的润湿能力。尤其是当wEr为0．05％～0．1％时最为显著．显微组织分析表明，随着wE4的增加，钎料显微组织细化，特别是针状共晶Si的长度逐渐减小．

Effect of Sb content on properties of Sn-Bi solders

The effect of Sb content on the properties of Sn-Bi solders was studied. The nonequilibrium melting behaviors of a series of Sn-Bi-Sb solders were examined by differential scanning calorimetry （DSC）. The spreading test was carried out to characterize the wettability of Sn-Bi-Sb solders on Cu substrate. The mechanical properties of the solders/Cu joints were evaluated. The results show that the ternary alloy solders contain eutectic structure resulting from quasi-peritetic reaction. With the increase of Sb content, the amount of the eutectic structure increases. At a heating rate of 5 ℃/min, Sn-Bi-Sb alloys exhibit a higher melting point and a wider melting range. A small amount of Sb has an impact on the wettability of Sn-Bi solders. The reaction layers form during spreading process. Sb is detected in the reaction layer while Bi is not detected. The total thickness of reaction layer between solder and Cu increases with the increase of the Sb content. The shear strength of the Sn-Bi-Sb solders increases as the Sb content increases.

混合稀土对Sr变质近共晶Al-Si合金组织的影响

研究了在Sr变质的近共晶Al 1 1 .6%Si(质量分数 )合金中加入混合稀土 (MM )对组织的影响。Sr对二次枝臂间距 (DAS)起着重要的作用 ,随着Sr含量的增加 ,DAS减小 ;随着MM加入量的增加 ,枝晶α的数量增加 ,主干长度缩短 ,存在等轴化趋向 ,但同时导致DAS增加 ,也导致共晶硅尺寸增大。MM的加入在某种程度上削弱了Sr的变质作用。

超高压凝固Al-Si合金的非平衡组织

研究了超高压（５．５ ＧＰａ）条件下凝固的过共晶 ＡＩ－Ｓｉ合金的非平衡组织．结果表明：过共晶成分合金中出现大量初生α 相，并有α＋β＋（α＋β）共晶的共生组织， Ｓｉ在α相中的固溶度和Ａｌ在β相中的固溶度都有极大增加．讨论了高压对凝固组织