Brazing of Cemented Carbides at Lower Temperatures

2011 ◽  
Vol 409 ◽  
pp. 865-870
Author(s):  
Shinji Yaoita ◽  
Takehiko Watanabe ◽  
Tomohiro Sasaki
Keyword(s):  
Mechanical Properties ◽  
Melting Point ◽  
Abrasion Resistance ◽  
Bending Strength ◽  
Filler Metal ◽  
Cutting Tools ◽  
High Hardness ◽  
Cemented Carbides ◽  
Brazed Joint ◽  
Tool Shank

Cemented carbides have been widely used for cutting tools because of their high hardness and abrasion resistance. Since the cemented carbides are so expensive, it is desirable to reuse a tool shank made of cemented carbides. For the reason, so far, a new blade of a tool has been brazed to used shanks. However, when cemented carbides are heated for brazing, heating inevitably causes the deterioration in the mechanical properties. This study was carried out to braze the cemented carbides at lower temperatures for reducing the deterioration of the shank. First of all, authors developed a new Ag-based brazing filler metal with a low melting point of about 605°C, and investigated the effects of the new Ag filler metal on the properties of a brazed joint. Moreover, Co element or Ni element was added into the Ag filler metal to make the bending strength of a brazed joint improved. The addition of Co element increased the bending strength of a joint and the strength was equivalent to that of a joint brazed at 750°C using a conventional Ag filler metal, but the addition of Ni element decreased the bending strength of a brazed joint.

Enhanced Mechanical Properties of SiCw/ SiCp-Reinforced Mg Composites Fabricated by Spark Plasma Sintering

2021 ◽  
Vol 878 ◽  
pp. 83-88
Author(s):  
Hideaki Tsukamoto ◽  
Chang Sun
Keyword(s):  
Mechanical Properties ◽  
Melting Point ◽  
Spark Plasma Sintering ◽  
Bending Strength ◽  
Oxide Layers ◽  
Plasma Sintering ◽  
Spark Plasma

This study aims to fabricate SiC whisker (w)/ particle (p)-reinforced magnesium (Mg) composites with enhanced mechanical properties using spark plasma sintering (SPS) methods. It has been confirmed that dispersing state of SiCw can be improved by addition of SiCp. However, due to presence of voids and cracks between the oxide layers, surrounding SiCw/p, and Mg matrix in the composites, SiCw with SiCp cannot contribute to enhance the bending strength of Mg matrix. This issue can be tackled by adding low melting point metals such as Sn into the composites to fill the defects in the composites.

Microstructure and Mechanical Properties of Sintered Fibrous Monolith Cemented Carbide

2013 ◽  
Vol 815 ◽  
pp. 233-239
Author(s):  
Xue Quan Liu ◽  
Cun Guang Ding ◽  
Chang Hai Li ◽  
Yi Li ◽  
Li Xin Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Crack Propagation ◽  
Fracture Energy ◽  
Bending Strength ◽  
Extrusion Process ◽  
Cemented Carbide ◽  
Cemented Carbides ◽  
Microstructure And Mechanical Properties

A fibrous monolith cemented carbide with WC-6Co as cell and WC-20Co as cell boundaries was produced through hot co-extrusion process in this paper. The density, hardness, bending strength and fracture toughness of the fibrous monolith cemented carbide were tested, and the fracture and crack propagation were observed by metalloscope and SEM. The results showed that the bending strength and fracture toughness of the fibrous monolith cemented carbides was remarkably improved 71.91% and 45.7% respectively, while the hardness was slightly decreased 1% compared with WC-6Co composites. It is the reason that the tougher shell WC-20Co with higher bending strength and fracture toughness can absorb more fracture energy, which can slow down and prevent the crack propagating from brittle core WC-6Co.

Effect of Ruthenium, Rhenium and Yttria Additions on the Microstructure of Wide Gap Brazing of IN738

2007 ◽  
Author(s):  
Xiao Huang ◽  
Scott Yandt ◽  
Doug Nagy ◽  
Matthew Yao
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Life Cycle Cost ◽  
Filler Metal ◽  
Braze Alloy ◽  
Cost Effective ◽  
Brazed Joints ◽  
Brazed Joint ◽  
Wide Gap ◽  
Boride Phases

Modern gas and steam turbine components are subject to severe thermomechanical loads and extremely high temperature in order to provide increased performance and efficiency. Most high temperature turbine components are made of superalloys specifically developed for high temperature and high mechanical stress applications but at considerable cost. Defects may occur during manufacturing of superalloy castings as well as after service. Repair of these components, rather than replacement, helps to reduce the life cycle cost. Wide gap brazing is a cost effective and reliable means to repair gas turbine hot section components with defect sizes exceeding 0.3 mm. With proper control of the braze alloy and brazing cycle, the repaired region has been reported to posses mechanical properties approaching that of the parent materials. In order to further improve the mechanical properties of the repaired region and to explore the possibility of employing the wide gap brazing method to repair single crystal components in the future, three alloying additions, Ruthenium (Ru), Rhenium (Re) and yttria (Y2O3), were incorporated into the braze filler metal by mechanical alloying. The microstructures of the wide gap brazed joints with Ru, Re and yttria additions were studied and compared to a braze joint with standard wide gap braze alloys of IN738 and AWS BNi-9. It has been found that two types of borides formed in all braze alloys, namely eutectic γ-Ni-rich and boride phases and discrete boride containing primarily Cr and W (or Ru). The addition of Ru to the filler metal did not seem to modify the microstructural constituents after brazing. However, Ru partitioned strongly to the discrete borides. No isolated elemental Ru region was observed. On the other hand, Re addition was found to change the occurrence and distribution of both types of borides. The eutectic boride constituent was significantly reduced and finer discrete boride particles were observed. The addition of yttria did not change the boride formation but led to the generation of more voids in the brazed joint.

Study of the mechanical properties and toughening mechanism of ZrO2 particles toughened Si3N4 ceramics

2020 ◽  
Vol 10 (6) ◽  
pp. 928-933
Author(s):  
Liang Tian ◽  
Qinglin Hou ◽  
Yingxia Wang ◽  
Yihui Hou
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Sintering Temperature ◽  
High Hardness ◽  
Fracture Morphology ◽  
Xrd Analysis ◽  
High Thermal Stability ◽  
Toughening Mechanism ◽  
Temperature Resistance ◽  
Si3n4 Ceramics

Si3N4 ceramic has excellent properties such as high temperature resistance, high hardness, and high thermal stability, but it has the disadvantages of high hardness and brittleness and difficulty in later processing. In this paper, ZrO2 was used as toughening phase, and ZrO2 toughened Si3N4 ceramics was prepared by injection molding. The effects of ZrO2 sintering temperature and content on the mechanical properties and fracture morphology were studied. Experiments show that when the ZrO2 content is 10 wt.% and the sintering temperature reaches 1650 °C, the bending strength and fracture toughness of Si3N4 ceramics reach the maximum at the same time, which are 767 MPa and 8.7 MPa·m1/2, respectively. The density is high. XRD analysis revealed that if the sintering temperature is too high, the ZrO2/Si3N4 system will generate a large number of ZrN impurity phases that cannot be phase-transformed, which ultimately affects the ceramic properties. According to fracture morphology, the toughening mechanism of ZrO2 is stress-induced phase transition.

Effect of Work Material’s Hardness on Cutting Performance of TiAlN- and CrAlN-Coated Cutting Tools

2015 ◽  
Vol 656-657 ◽  
pp. 231-236
Author(s):  
Risa Koda ◽  
Hiroshi Usuki ◽  
Masahiro Yoshinobu ◽  
Kana Morishita ◽  
Shuho Koseki ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Brinell Hardness ◽  
Cutting Tools ◽  
High Hardness ◽  
Superior Performance ◽  
End Mills ◽  
Arc Evaporation ◽  
Cutting Experiments ◽  
Cutting Speeds ◽  
Selection Of

For better selection of coated cutting tools, TiAlN (Ti50Al50N) and CrAlN (Cr50Al50N) coatings were deposited onto ball-nose and square end mills using arc evaporation, and their cutting performances were evaluated using steel workpieces of various hardnesses. In particular, cutting tests were performed on three types of workpieces, made from S50C, SKD61, and SKD11 steels, having Brinell hardness numbers of HB220, HRC40, and HRC60, respectively. The results of the cutting experiments were elucidated and discussed in terms of the mechanical properties and anti-oxidation resistances of the different coatings. The results revealed that TiAlN-coated square end mills at high cutting speeds (V = 200 m/min ) had superior performance when used on steels with high hardness (SKD11), whereas CrAlN-coated ball-nose end mills were superior when used on low hardness steel (S50C). Therefore, CrAlN-coated ball-nose end mills are concluded to be suitable for the machining of low hardness steels, whereas TiAlN-coated square end mills are preferable for the machining of high hardness steels (SKD11).

Effect of calcium on the microstructure and mechanical properties of brazed joint using Ag–Cu–Zn brazing filler metal

2013 ◽  
Vol 46 ◽  
pp. 605-608 ◽  
Author(s):  
Fangfei Sui ◽  
Weimin Long ◽  
Shengxin Liu ◽  
Guanxing Zhang ◽  
Li Bao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Filler Metal ◽  
Microstructure And Mechanical Properties ◽  
Brazed Joint

scholarly journals Investigation of the Wear Performance of TiB2 Coated Cutting Tools during the Machining of Ti6Al4V Alloy

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2799
Author(s):  
Mohammad Shariful Islam Chowdhury ◽  
Bipasha Bose ◽  
German Fox-Rabinovich ◽  
Stephen Clarence Veldhuis
Keyword(s):  
Mechanical Properties ◽  
Tool Life ◽  
Cutting Tools ◽  
Chip Morphology ◽  
High Hardness ◽  
Ti6al4v Alloy ◽  
Wear Volume ◽  
Coating Delamination ◽  
Rough Turning ◽  
Coated Carbide

The machining of Ti6Al4V alloy, especially at low cutting speeds, is associated with strong Built-Up Edge (BUE) formation. The PVD coatings applied on cutting tools to machine such materials must have the necessary combination of properties to address such an underlying wear mechanism. The present work investigates and shows that TiB2 PVD coating can be designed to have certain mechanical properties and tribological characteristics that improve machining in cases where BUE formation is observed. Three TiB2 coatings were studied: one low hardness coating and two high hardness coatings with varied coating thicknesses. Wear performances for the various TiB2 coated carbide tools were evaluated while rough turning Ti6Al4V. Tool wear characteristics were evaluated using tool life studies and the 3D wear volume measurements of the worn surface. Chip morphology analyses were done to assess the in-situ tribological performance of the coatings. The micro-mechanical properties of the coatings were also studied in detail to co-relate with the coatings’ performances. The results obtained show that during the rough turning of Ti6Al4V alloy with intensive BUE formation, the harder TiB2 coatings performed worse, with coating delamination on the rake surface under operation, whereas the softer version of the coating exhibited significantly better tool life without significant coating failure.

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