单向拉伸聚乙烯薄膜应力-应变曲线的分析

采用拉伸实验的方法。研究了形变速率对半晶聚乙烯薄膜拉伸性能的影响。根据其应力-应变曲线的形状，得出聚乙烯具有两个屈服点，研究了这两个屈服点与拉伸速率的关系。并从微观结构的角度对此进行了解释。     

聚乙烯薄膜表面放射线改性

聚乙烯薄膜表面放射线改性聚乙烯薄膜价格便宜，用途广泛。但由于没有极性基团不能粘接和印刷。用电晕放电方法进行表面改性，印刷性能有所改善，但仍不尽人意。近年来采用放射线照射进行表面改性，粘接性能明显提高。改性用的聚乙烯薄膜，可用线型低密度薄膜（ＬＬＤ），...     

偶联剂处理滑石粉填充聚乙烯薄膜的研究

目的确定最佳偶联剂及其用量,以改进聚乙烯薄膜的综合性能。方法采用铝酸酯、钛酸酯、硬脂酸等偶联剂对滑石粉进行表面改性,通过测定改性后滑石粉的接触角、活化率以及红外光谱等方法对改性效果进行评价。并将改性后的滑石粉与聚乙烯共混后进行吹塑薄膜,测定薄膜的力学性能。结果采用偶联剂改性滑石粉后,表面从亲水性变为疏水性,其中钛酸酯表面改性效果较好。表面改性提高了滑石粉填充聚乙烯薄膜的力学性能。结论使用质量分数为2%钛酸酯改性的滑石粉作为填充粉体时,聚乙烯薄膜的综合性能较好。     

有机硅玻璃漆布用作热焊聚乙烯薄膜隔离布

我厂过去采用聚氯乙烯薄膜包装产品,是用高频电子热合机进行焊接的。为了改进包装质量,自1969年起改用透水性小的聚乙烯薄膜包装产品。改用聚乙烯薄膜后,直接用高频电子热合机焊接效果不好。为了提高焊接质量,曾在焊刀与聚乙烯薄膜之间垫一层聚氯乙烯薄膜,焊好后再将聚氯乙烯薄膜剥下来,这样又很麻烦。后来我们自制了电加热的手提式焊刀,     

对Ag/Cu薄膜退火应力的模拟

采用基片曲率法测量并研究了Ag／Cu薄膜的应力与温度的关系．初始应力为-250MPa压应力，退火后为370MPa拉应力．采用基于形变机制图的模型模拟了应力与温度关系的实验曲线，结果表明，温度和应力不同，在薄膜内起作用的主要形变机制也不同．可能的形变机制包括位错滑移、幂律蠕变以及扩散蠕变机制．薄膜比块体材料的应变速率低，在同样的应力下应变更加困难．在退火过程中，薄膜内先使应力松弛的是Ag，将Ag各蠕变机制中的激活能提高到块体材料的1.25～1.35倍，模拟曲线与实验曲线符合得很好。     

包装用低密度聚乙烯的动向

包装用低密度聚乙烯的动向从有效利用低密度聚乙烯特性和市场具体情况看，低密度聚乙烯将向薄膜、层压品、电缆等主要用途方面发展、薄膜和层压品大都用作包装材料。目前，包装用材料主要是指拉伸薄膜和复合薄膜。随着包装机的发展，拉伸包装开始使用低密度聚乙烯薄膜，以...     

超高分子量聚乙烯表面金属化及类金刚石薄膜沉积复合处理研究

采用超高分子量聚乙烯(UHMWPE)表面金属化及类金刚石薄膜沉积复合处理工艺,提高超高分子量聚乙烯的耐磨性.首先采用磁过滤阴极真空弧源沉积技术(FCVA)在UHMWPE表面制备约30nm钛金属层,使UHMWPE表面金属化,然后再沉积DLC薄膜,研究结果表明,UHMWPE表面金属化后,DLC薄膜沉积过程中,电荷累积效应消...     

改性聚乙烯防雾薄膜的性能研究

用表面活性剂对聚乙烯(PE)树脂进行改性,制备防雾薄膜,使其具有防雾作用。以聚乙烯蜡乳液(WE1)为分散剂,防雾母粒(YS)、聚甘油脂肪酸酯(PGFE)作为防雾剂,对PE树脂进行改性,混合造粒后流延制备出聚乙烯防雾薄膜。研究了改性聚乙烯薄膜的微观结构、防雾性能、力学、光学、透气、透湿及热稳定性能。结果表明,防雾剂与聚乙烯薄膜相容性好,改善了聚乙烯薄膜的阻隔性,并且使薄膜具有优良的防雾性能。YS的加入使薄膜拉伸强度增大,当YS,PGFE分别以2%复配时,薄膜透光率为86.22%,拉伸强度为8.63 MPa,断裂伸长率为453.31%,高温防雾时间可达232h,可以作为防雾包装薄膜使用。     

聚丙烯包装薄膜形变性能的研究

采用拉伸实验,研究形变速率对聚丙烯包装薄膜屈服强度和断裂强度的影响,同时研究在80℃条件下热氧老化处理聚丙烯包装薄膜后,老化时间对材料屈服强度和弹性模量的影响。     

真空镀二氧化钛聚乙烯塑料包装薄膜

塑料包装薄膜上进行无机氧化物镀层在材料科学领域和包装应用领域都有重要的意义.采用蒸镀、多弧镀和硅油轰击蒸镀3种真空镀膜方法,在聚乙烯塑料包装薄膜上实现了的二氧化钛镀膜.采用扫描电镜、X-射线衍射、气体渗透、透湿性、紫外分光等进行了表征和性能研究.结果表明在聚乙烯塑料包装薄膜上成功实现了二氧化钛镀膜;真空镀二氧化钛聚乙烯薄膜的气体阻隔性能大大提高,其气体透过量约为原聚乙烯薄膜的0.1%～1%;水汽阻隔性也有所提高;并表现出较好的紫外线屏蔽性能.     

聚丙烯薄膜形变对微观结构的影响

用X射线衍射的方法分析了聚丙烯流延薄膜受单向拉仲作用后形变的微观结构,得到了形变后微晶尺寸和点阵畸变的数值,找出了聚集态精细结构随形变而变化的微观规律。     

应力作用下X80钢焊接接头在近中性pH值溶液中的电化学行为研究

管线钢近中性p H值环境应力腐蚀开裂(SCC)是管线失效的一种重要形式,但其发生机理仍不清楚,现场实际发现其易发生在焊缝附近。采用动电位极化和电化学阻抗技术研究了外加拉应力对X80钢焊接接头在近中性p H值溶液中电化学行为的影响。结果表明:应力使X80钢母材和焊缝的腐蚀电位负移,腐蚀电流密度增大,应力促进了母材和焊缝的阳极溶解和阴极反应;在弹性变形区间,外加应力没有破坏腐蚀产物膜的完整性,腐蚀产物膜电阻几乎不变,应力使腐蚀产物膜孔隙结构变大,促进侵蚀性离子向电极表面扩散,母材和焊缝的电荷转移电阻明显减小;由于组织结构的原因,焊缝的应力影响系数比母材的大,X80钢焊缝比母材有更强的应力敏感性。     

Uniaxial tensile and shear deformation tests of gold-tin eutectic solder film

This paper describes a novel experimental technique for measuring mechanical properties of gold-tin (Au-Sn) eutectic solder film used for soldering package in microelectromechanical systems (MEMS). Dual-source DC magnetron sputtering was employed to deposit Au-20 weight % (wt%) Sn film. The tensile test with in situ X-ray diffraction (XRD) measurement evaluates the Young's modulus and Poisson's ratio at intermediate temperatures. The Young's modulus and Poisson's ratio at room temperature were found to be 51.3 GPa and 0.288, lower than bulk values. The Young's modulus decreased with increasing temperature, whereas the Poisson's ratio did not depend on temperature. The XRD tensile test also showed creep deformation behavior of Au-Sn film. We have developed a shear deformation test technique, which is performed by using Au-Sn film sandwiched by two single crystal silicon (Si) cantilever structures, to characterize the shear properties of the film. The shear moduli obtained from the shear deformation tests ranged from 11.5 to 13.3 GPa, about 38% lower than those from the XRD tensile tests. The measured shear strength from 12 to 17 MPa exhibited a temperature dependency. Information about the tensile and shear characteristics would likely to be of great use in designing Au-Sn soldering packages for MEMS.     

Tension behavior of metallic glass coating on Cu foil

The tensile behavior of the monolithic ZrCu thin film metallic glass and the ZrCu/Cu multilayer coating on pure Cu foil is systematically examined. The extracted tensile modulus and strength of the 1 μm films are in good agreement with the theoretical rule of mixture prediction. The extracted 2 μm film data are lower, but can be corrected back by considering the actual intact cross-sectional area during the tensile loading. The current results reveal that the ZrCu/Cu multilayer coating exhibit much better tensile performance than the monolithic ZrCu coating despite of the brittle deformation. To obtain ductile amorphous/crystalline multilayer coating, two principles are suggested in this paper.     

Deformation and fracture behavior of electrocodeposited alumina nanoparticle/copper composite films

Electrocodeposition of alumina nanoparticles and copper thin film on silicon wafers was performed. The volume fraction of the nanoparticle is about 5% and the size is about 50 nm. Comparison between the static tensile behaviors of specimens with and without nanoparticles reveals that the Young’s modulus is significantly increased by incorporating nanoparticles into the copper film. However, the ultimate tensile strength of the nanocomposite (235 MPa) is slightly lower than that of the pure copper reference specimen (250 MPa). For the nanocomposite, the strain at failure is 7.8%, which is lower than that of the pure copper film (10.5%). Distinct microscale deformation mechanisms are observed: the main deformation mechanism of the pure copper film is slip followed by strain hardening, whereas for the nanocomposite, multistage failure behaviors are found due to the debonding at the nanoparticle/copper interface. Notched specimens were also tested and compared with the unnotched specimens. In addition, cyclic loading tests on the nanocomposite were conducted to show its hardening behavior.     

The Mechanical and Adhesion Properties of Aqueous Based Hydroxypropyl Methylcellulose Coating Systems Containing Polydextrose and Titanium Dioxide

The effect of titanium dioxide and polydextrose on film adhesion to microcrystalline cellulose tablet surface and mechanical properties of aqueous-based hydroxypropyl methylcellulose free films were evaluated using a Lloyd LRX materials testing machine. The free films and the films applied to tablets were prepared by using a pneumatic spraying technique similar to that used in fluidized-bed coaters.

The film adhesion was found to increase with increasing concentrations of titanium dioxide and polydextrose in the film. The addition of polydextrose to the film increased only slightly the moisture permeation of coated tablets. This may be due to the hygroscopic nature of polydextrose. Over the range studied, the addition of polydextrose reduced the elongation and the tensile strength of the film, indicating decreased deformation capacity of the film and a risk of cracking.     

中锰Q&P钢残余奥氏体的稳定性及其TRIP效应

通过单向拉伸及平面应变实验研究了Mn含量为7%的中锰淬火-配分(QP)钢残余奥氏体的机械稳定性,利用X射线衍射仪(XRD)测定试验钢残余奥氏体的含量,通过观察试验钢的拉伸曲线及扫描电镜(SEM)、透射电镜(TEM)照片,分析变形前后的微观组织,研究中锰QP钢的变形机制。结果表明:应力状态对残余奥氏体稳定性有较大的影响,平面应变更有利于相变诱导塑性(TRIP)效应的发挥;中锰QP钢的拉伸变形特征是由超细晶硬化机制和TRIP效应相互作用产生的,通过微观组织观察发现中锰QP钢的塑性变形主要是残余奥氏体的TRIP效应,其中薄膜状的残余奥氏体的稳定性最高。     

Damage mode tensile testing of thin gold films on polyimide substrates by X-ray diffraction and atomic force microscopy

In situ tensile testing has been performed on thin gold film, 320 nm thick, deposited on polyimide substrates. During the tensile testing, strain/stress measurements have been carried out by X-ray diffraction using the d-sin²ψ method. The X-ray stress analysis suggests crack formation in the films for stresses greater than 670 MPa. The surface of the deformed specimen observed by atomic force microscopy (AFM) exhibits both cracks and two types of straight-sided buckling patterns lying perpendicular to the tensile axis. These buckling patterns can have a symmetrical or asymmetrical shape. The evolution of these two kinds of buckling structures under tensile stress has been observed in situ by AFM and compared to X-ray stress data. The results indicate that symmetrical straight-sided buckling patterns are induced by the compressive stress during unloading, whereas the asymmetrical result from the delamination of the film during the tensile deformation.     

基于数字散斑相关方法的VCM深冲钢板力学性能评价

目的针对VCM深冲钢板各组分材料在变形过程中很难达到屈服和破坏的同步,材料很容易在附加应力的作用下沿薄弱方向产生失效乃至断裂的问题,研究在外加及内在因素影响下材料的变形机理和变形过程。方法采用数字散斑相关方法对VCM深冲钢板及其组分材料的力学性能进行研究。引入偏离系数、影响系数、梯度系数来计算VCM深冲钢板及其组分材料之间的关系,获取试样拉伸过程中三维变形的几何数据。结果得到了VCM深冲钢板及其组分材料的抗拉强度、弹性模量、上屈服强度、最大力下总伸长率和断后伸长率,其中,深冲基板影响系数达到2.582,影响最小的是最大力下总伸长率,影响系数为0.806。通过XJTUDIC系统检测并分析获得了x和y方向的位移值、应变值和最大主应变值。结论增加VCM薄膜后,VCM深冲钢板的应力应变能力有所提高,VCM薄膜最大应变值为91.632%,深冲基板最大应变值为40.068%,VCM深冲钢板的最大应变值为41.632%,其力学性能介于深冲基板和VCM薄膜力学性能之间。     

A study towards improving mechanical properties of sol-gel coatings for polycarbonate

Scratch-resistant coatings based on 3-glycidoxypropyltrimethoxysilane and tetraethylorthosilicate with a cross-linking agent and different amounts of colloidal silica are prepared on polycarbonate substrates by sol-gel technique. The failure mode of this type of coating on soft plastic substrate under pencil scratch test is studied. It is found that the pencil scratch failure contains a gouge failure under the static pressure and a film cracking failure under the sliding of the pencil tip. The gouge failure is due to the early plastic deformation in the substrate, while the film cracking is due to the tensile stress in the film induced by the sliding and friction of the pencil tip. Factors influencing the static gouge failure and sliding cracking failure are investigated. It is found that the cross-linking agent and colloidal silica filler increase the intrinsic cross-linking, hardness, elastic modulus and fracture toughness of the coating material, therefore, reduce the film cracking tendency; whereas the increased layer thickness and multi-layer coating improve the pencil scratch resistance significantly via delayed plastic deformation in the substrate. Based on these analyses, we conclude that the main factors towards improved pencil scratch resistance are: layer thickness, elastic modulus, fracture toughness and intrinsic hardness of the coating material. Pencil hardness is increased from grade 2B to 5H by adjusting these parameters.