Ultrasonic Torsional Welding of Metal/Glass Ceramics Joints

2019 ◽  
Vol 809 ◽  
pp. 237-244
Author(s):  
Andreas Gester ◽  
Guntram Wagner
Keyword(s):  
Mechanical Characterization ◽  
Glass Ceramics ◽  
Dissimilar Materials ◽  
High Strength ◽  
Tensile Shear ◽  
Shear Tests ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
Solid State Joining ◽  
Welding Technique

Ultrasonic welding is a suitable solid-state joining technique for producing high strength joints of similar or dissimilar materials, even of material combinations that were previously considered as not weldable. Several varieties of transmitting the ultrasound into the joining partners exist whereas the investigated torsional welding principle utilizes a ring shaped sonotrode for transmitting ultrasonic vibrations tangentially to the welding force into the workpiece. Due to the specific sonotrode geometry ultrasonic torsional welding is a remarkably gentle welding technique, allowing to join even most sensitive components e.g. sensors or brittle elements. Nevertheless, ultrasonic torsional welded joints show high tensile strengths and helium-tightness. Current investigations focus on the realization of metal/glass ceramics joints. In this project two metals with different thermal expansion coefficients have been utilized as the metal joining partner. The glass joining partner was the commercially available Li2O-Al2O3-SiO2 CERAN. For examining the microstructure light as well as scanning electron microscopy have been performed. Additionally, mechanical characterization has been carried out through tensile shear tests.

Some recent developments in high-strength glasses and ceramics

1964 ◽  
Vol 282 (1388) ◽  
pp. 52-56
Keyword(s):  
Thermal Expansion ◽  
Bending Strength ◽  
Glass Ceramics ◽  
High Strength ◽  
Fine Grained ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Recent Developments ◽  
Expansion Coefficients ◽  
Mechanical Strengths

Two areas of development in the field of glasses and ceramics have produced new materials with unusual combinations of properties. Glass-ceramics are melted and formed as glasses by conventional glass-forming techniques, but by a subsequent heat treatment, they are converted to fine-grained crystalline structures with new and useful combinations of properties. Products with thermal expansion coefficients approaching zero and flexural strengths ranging from 10 000 to 50 000 Lb./in. 2 have been made though not all combinations of low thermal expansion coefficients and high mechanical strengths are possible. The second area of development is in so-called Chemcor glasses. Such glass products can be preferentially pre-stressed by chemical means so as to produce an outer layer with high compressive stress and a bending strength in the finished product up to 100 000 Lb/in. 2 .

Investigation on Glasses in Strontium Zinc Borosilicate System as Sealants for Solid Oxide Fuel Cell

2012 ◽  
Vol 585 ◽  
pp. 195-199 ◽  
Author(s):  
Babita Tiwari ◽  
S.C. Gadkari ◽  
G.P. Kothiyal
Keyword(s):  
Heat Treatment ◽  
Glass Ceramics ◽  
Glass Network ◽  
Solid Solution Phase ◽  
Structural Units ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
Zinc Borosilicate ◽  
B2o3 Glass ◽  
Quench Method

Glasses in the SrO-ZnO-B2O3-SiO2 (SZBS) system with different additives like V2O5, Cr2O3, TiO2, and Al2O3 have been prepared by melt-quench method. Glasses were subjected to controlled heat treatment for conversion into glass-ceramics. Investigated glasses and glass-ceramics have thermal expansion coefficients (TEC) in the range of 95-120 x 10-7/oC (30-600 oC) which closely match with TEC of other SOFC components. XRD indicates the crystallization of Sr2ZnSi2O7 solid-solution phase in glasses upon heat treatment. Structural studies revealed that mainly Q1 and Q2 silicate structural units are present in the glass network and B2O3 enters in the network as triangular borate (BO3) structural units. Only small fraction of B2O3 enters as tetragonal borate (BO4) structural units at higher concentration of B2O3. Glass network depolymerizes with the addition of additives and concentration of Q1 units increases at the expense of Q2 units. Small addition of V2O5 in SZBS glass is beneficial for increasing TEC and achieving better flowability at lower sealing temperature. Studied SZBS glasses also show good bonding with Crofer-22-APU. Elemental line scans indicate that interdiffusion of Fe, Cr, Sr and Si across interface is responsible for good bonding with Crofer-22-APU. To show suitability of material for high temperature sealing, seals have been prepared and tested for vacuum integrity at 850oC for 500h.

Properties of ZrO2/Glass-Ceramics Composite

2007 ◽  
Vol 280-283 ◽  
pp. 995-998
Author(s):  
Y.M. Zhu ◽  
Xia Wan Wu ◽  
Zhi Hong Li
Keyword(s):  
Thermal Expansion ◽  
Flexural Strength ◽  
Glass Powder ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Glass Ceramics ◽  
Glass Content ◽  
Thermal Expansion Coefficients ◽  
Lower Thermal Expansion ◽  
Expansion Coefficients

In order to reduce the raw materials cost, lower the sintering temperature of 3Y-TZP optical fiber ferrules, the 3Y-TZP/ LAS glass ceramics composites were prepared and their properties were investigated in this paper. The results showed that the sintering temperatures and thermal expansion coefficients of the 3Y-TZP/LAS glass ceramics composites were lowered with the increase of glass content. The flexural strength of the composites were decreased with the increase of glass content, but the flexural strength of the composite with 15% weight glass was higher than 400MPa. The LAS glass powder added into the composites was crystallized and b-spodumene s.s was precipitated. during sintering. The b-spodumene s.s. having lower thermal expansion coefficient and higher strength was beneficial to reduce thermal expansion coefficients and keep higher strengths of the composites .

Thermal Stress Analysis of a Bi-Material Layered Structure

2010 ◽  
Vol 450 ◽  
pp. 161-164 ◽  
Author(s):  
Shiuh Chuan Her ◽  
Chin Hsien Lin ◽  
Shun Wen Yeh
Keyword(s):  
Thermal Expansion ◽  
Thermal Stress ◽  
Thermal Stresses ◽  
Dissimilar Materials ◽  
Beam Theory ◽  
Layered Systems ◽  
Thermal Expansion Coefficients ◽  
Parametric Studies ◽  
Expansion Coefficients ◽  
Good Agreement

Thermal stress induced by the mismatch of the thermal expansion coefficients between dissimilar materials becomes an important issue in many bi-layered systems, such as composites and micro-electronic devices. It is useful to provide a simple and efficient analytical model, so that the stress level in the layers can be accurately estimated. Basing on the Bernoulli beam theory, a simple but accurate analytical formulation is proposed to evaluate the thermal stresses in a bi-material beam. The analytical results are compared with finite element results. Good agreement demonstrates that the proposed approach is able to provide an efficient way for the calculation of the thermal stresses. It is shown that thermal stresses are linear proportion to the ratio of thermal expansion coefficients between the two materials. Parametric studies reveal that thermal stresses in each layer are decreasing with the increase of thickness, and are increasing with the increase of Young’s modulus ratio between the two materials.

Properties and crystallization of Li2O–CaO–Al2O3–SiO2–TiO2glasses

1993 ◽  
Vol 8 (4) ◽  
pp. 890-898 ◽  
Author(s):  
Moo-Chin Wang ◽  
Min-Hsiung Hon
Keyword(s):  
Thermal Expansion ◽  
Thermal Properties ◽  
Diffraction Analysis ◽  
Crystalline Phase ◽  
Glass Ceramics ◽  
Weight Percent ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

The addition of CaO to Li2O–Al2O3–SiO2–TiO2(LAST), forming the Li2O–CaO–Al2O3–SiO2–TiO2(LCAST) system, is used in the preparation of low themal expansion coefficient glass-ceramics. By a progressive weight percent substitution of CaO for SiO2, at constant ratios of concentration of Li2O, Al2O3, and TiO2, a number of properties of these glasses have been studied. The results indicated that these thermal properties increased progressively with increasing CaO concentration. X-ray diffraction analysis was utilized to identify the crystalline phase in glass-ceramics of the Li2O–CaO–Al2O3–SiO2-TiO2system. Thed-spacings of the major crystallites were precisely measured and fitted with those of β-spodumene. The minor crystalline phase of titanite, CaO · TiO2· SiO2, was also present. The average thermal expansion coefficients from 25 to 700 °C were 3.50 × 10−6/°C, 3.81 × 10−6/°C, and 3.91 × 10−6/°C for samples A, B, and C, respectively.

scholarly journals Experimental Study on Joining by Forming of HCT590X + Z and EN-AW 6014 Sheets Using Cold Extruded Pin Structures

2021 ◽  
Vol 5 (1) ◽  
pp. 25
Author(s):  
David Römisch ◽  
Martin Kraus ◽  
Marion Merklein
Keyword(s):  
Joint Strength ◽  
Dissimilar Materials ◽  
High Strength ◽  
Linear Increase ◽  
Cold Extrusion ◽  
Manufacturing Processes ◽  
Average Height ◽  
Tensile Shear ◽  
Material Systems ◽  
The Right

Due to stricter emission targets in the mobility sector and the resulting trend towards lightweight construction in order to reduce weight and consequently emissions, multi-material systems that allow a material to be placed in the right quantity and in the right place are becoming increasingly important. One major challenge that is holding back the rapid and widespread use of multi-material systems is the lack of adequate joining processes that are suitable for joining dissimilar materials. Joining processes without auxiliary elements have the advantage of a reduced assembly effort and no additional added weight. Conventional joining processes without auxiliary elements, such as welding, clinching, or the use of adhesives, reach their limits due to different mechanical properties and chemical incompatibilities. A process with potential in the field of joining dissimilar materials is joining without an auxiliary element using pin structures. However, current pin manufacturing processes are mostly time-consuming or can only be integrated barely into existing industrial manufacturing processes due to their specific properties. For this reason, the present work investigates the production of single- and multi-pin structures from high-strength dual-phase steel HCT590X + Z (DP600, t0 = 1.5 mm) by cold extrusion directly out of the sheet metal. These structures are subsequently joined with an aluminium sheet (EN AW-6014-T4, t0 = 1.5 mm) by direct pin pressing. For a quantitative evaluation of the joint quality, tensile shear tests are carried out and the influence of different pin heights, pin number, and pin arrangements, as well as different joining strategies on the joint strength is experimentally evaluated. It is proven that a single pin structure with a diameter of 1.5 mm and an average height of 1.86 mm achieves a maximum tensile shear force of 1025 N. The results reveal that the formation of a form-fit during direct pin pressing is essential for the joint strength. By increasing the number of pins, a linear increase in force could be demonstrated, which is independent of the arrangement of the pin structures.

Study on the Cracking of SiO2-TiO2 Films Prepared by Sol-Gel Method

2005 ◽  
Vol 475-479 ◽  
pp. 1227-1230 ◽  
Author(s):  
Feng Zhou ◽  
Kai Ming Liang ◽  
Hua Shao
Keyword(s):  
Heat Treatment ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Dip Coating ◽  
Tetraethyl Orthosilicate ◽  
Heating Process ◽  
Tio2 Films ◽  
Cracking Behavior ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

In this paper, the cracking behavior of sol-gel-derived SiO2-TiO2 films on glass-ceramics substrates is characterized by means of DTA, XRD and SEM. The SiO2-TiO2 films are deposited by sol-gel dip coating with tetrabutyl orthotitanate (Ti(OBu)4) and tetraethyl orthosilicate (TEOS) as raw precursors. The result shows that the cracking of the films is mainly related to the surface cleanliness of the substrate, the thermal expansion coefficients of the film and the substrate, the viscosity of the mixed sol, and the unbalanced stress produced during drying and heating process. The films without cracks were obtained by modifying the composition of sol and controlling the relative humidity and the heating rate of heat treatment.

Amorphous Compositions for Production of Thick Films

2008 ◽  
Vol 575-578 ◽  
pp. 1111-1116
Author(s):  
Janina Setina ◽  
V. Akishins
Keyword(s):  
Chemical Reactivity ◽  
Thick Films ◽  
Glass Ceramics ◽  
Phosphate Glasses ◽  
Borosilicate Glasses ◽  
Structural Elements ◽  
Thermal Expansion Coefficients ◽  
Wide Range ◽  
Phosphorus Containing ◽  
Expansion Coefficients

The article gives an overview of suitability of three kinds of phosphorus-containing glass systems: phosphate, alumosilicate phosphate and fluorophosphate for production of thick-films. Amorphous compositions based on metaphosphate glasses characterize high electric resistivity, thermal expansion coefficients matching with substrate, appropriate viscosity-temperature relationship, and suitable chemical reactivity, that they can be applied in thick-film technology for screen printed resistors on alumina substrate as an alternative of lead borosilicate glasses. Alumosilicate phosphate glasses are the base for the wide range of glass-crystalline high temperature materials (operating up to 10000C) for sealing of the silicon chip in microelectronics. Perfect adhesion of glass ceramics with substrate (the transition zone 5-7.5 μm) is provided by the formation of chemical bond with the oxidized surface of silicon and by the occurrence of analogous structural elements on the silicon surface and in the glass-ceramics. Due to the unique optical properties, low melting temperature of fluorine containing borophosphate glasses (FBP) can be used as brazing material (optical glue) for SiO2 glass optical fiber construction knots.

CHARACTERISTICS OF AA7075-T6 AND AA6061-T6 FRICTION WELDED JOINTS

2015 ◽  
Vol 39 (4) ◽  
pp. 845-854 ◽  
Author(s):  
Sathish Rengarajan ◽  
Vaddi Seshagiri Rao
Keyword(s):  
Experimental Study ◽  
Mechanical Characterization ◽  
Dissimilar Materials ◽  
High Strength ◽  
Structural Behavior ◽  
Direct Drive ◽  
Parent Metal ◽  
Interface Zone ◽  
Eutectic Particles ◽  
Distinctive Difference

In this experimental study dissimilar materials of AA6061-T6 and AA7075-T6 having distinctive difference in physical and thermal properties were welded using continuous direct drive friction welding. High strength was achieved by high friction, upset pressure, low burn off length and medium rotational speed. Mechanical characterization and Micro structural behavior of the joint were given the paramount importance in this experimental analysis. The macro structure indicates that change in the direction of flow of grains perpendicular to the initial grain direction of the parent metal. Also the micro structural analysis at the interface zone showed the presence of eutectic particles that are formed as fragmented agglomerates.

Defects in β-SiC thin films grown on α-SiC substrates

1988 ◽  
Vol 46 ◽  
pp. 568-569
Author(s):  
Karren L. More
Keyword(s):  
Thin Films ◽  
Semiconductor Device ◽  
Lattice Mismatch ◽  
Chemical Vapor ◽  
Substrate Material ◽  
Growth Interface ◽  
Si Substrates ◽  
Thermal Expansion Coefficients ◽  
Device Applications ◽  
Expansion Coefficients

Beta-SiC is an ideal candidate material for use in semiconductor device applications. Currently, monocrystalline β-SiC thin films are epitaxially grown on {100} Si substrates by chemical vapor deposition (CVD). These films, however, contain a high density of defects such as stacking faults, microtwins, and antiphase boundaries (APBs) as a result of the 20% lattice mismatch across the growth interface and an 8% difference in thermal expansion coefficients between Si and SiC. An ideal substrate material for the growth of β-SiC is α-SiC. Unfortunately, high purity, bulk α-SiC single crystals are very difficult to grow. The major source of SiC suitable for use as a substrate material is the random growth of {0001} 6H α-SiC crystals in an Acheson furnace used to make SiC grit for abrasive applications. To prepare clean, atomically smooth surfaces, the substrates are oxidized at 1473 K in flowing 02 for 1.5 h which removes ∽50 nm of the as-grown surface. The natural {0001} surface can terminate as either a Si (0001) layer or as a C (0001) layer.

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