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Hot Hardness (hot + hardness)

Distribution by Scientific Domains
Polymers and Materials Science100%

Selected Abstracts

Microstructure and Mechanical Properties of New AlCoxCrFeMo0.5Ni High-Entropy Alloys

ADVANCED ENGINEERING MATERIALS, Issue 1-2 2010
Chin-You Hsu
Effects of Co content on microstructures and hot hardness of a new high-entropy alloy system, AlCoxCrFeMo0.5Ni (x,=,0.5 to 2.0) were investigated. As cobalt content increases, the microstructure changes from dendrite to polygrain type and the constituent phases change from BCC,+,, at x,=,0.5 to BCC,+,FCC,+,, at x,=,2.0. The alloy hardness varies from Hv 788 at x,=,0.5 to Hv 596 at x,=,2.0. This can be explained with the relative amount of hard , phase, medium hard BCC phase and soft FCC phase. All the AlCoxCrFeMo0.5Ni alloys possess higher hardness level than that of Ni-based superalloys In 718/In 718 H from room temperature to 1273,K. They obey the Westbrook equation presenting the normal heating behavior. Both alloys of x,=,0.5 and 1.0 exhibit a transition temperature higher than that of Co-based alloy T-800 by about 200,K. They also have a high hot hardness of Hv 347 at 1273,K, which is higher than those of In 718 and In718 H by Hv 220. The strengthening mechanism for their superiority is proposed. The AlCoxCrFeMo0.5Ni alloy system has great potential in high-temperature applications. [source]

Crystalline , -Alumina Deposited in an Industrial Coating Unit for Demanding Turning Operations,

ADVANCED ENGINEERING MATERIALS, Issue 1-2 2010
Kirsten Bobzin
Crystalline PVD ,-Al2O3 - coatings offer great potential for their use in high-speed cutting operations. They promise high hot hardness and high oxidation resistance at elevated temperatures. This is important for coatings that are used for machining of materials with low thermal conductivity such as stainless steel or Inconel 718 because heat generated during cutting can barely be dissipated by the chip. Because of the prevailing bonding forces of alumina, adhesion-related sticking can be reduced even for dry cutting. Furthermore, the high formation enthalpy of alumina prevents chemical reactions with frictional partners. The present work gives an overview of the deposition of ,-Al2O3 thin films on WC/Co-cutting inserts by using pulsed MSIP (magnetron sputter ion plating) PVD technology. To improve adhesion, a (Ti,Al)N bond coat was employed. The samples were analyzed using common thin film test equipment. Cutting tests and pin-on-disk examinations were carried out to test the coating's performance. For turning operations, the difficult-to-machine austenitic steel 1.4301 (X5CrNi18-10) was used. In comparison to a state-of-the-art (Ti,Al)N coating, (Ti,Al)N/,-Al2O3 showed a longer tool life. [source]

Thermal Investigation of Al2O3 Thin Films for Application in Cutting Operations,

ADVANCED ENGINEERING MATERIALS, Issue 7 2009
Kirsten Bobzin
Crystalline PVD ,-Al2O3 coatings offer great potential for use in high-speed cutting operations. They offer specific high temperature features, like high hot hardness and high oxidation resistance. However, the reasons for the high thermal stability of this system are not clearly understood. In this paper, the phase and oxidation stability of thin ,-Al2O3 films (as illustrated in the micrograph) are investigated. [source]

Pulsed Nanocomposite TiAlN Coatings on Complex Shaped Tools for High Performance Cutting Operations

PLASMA PROCESSES AND POLYMERS, Issue S1 2007
Kirsten Bobzin
Abstract The demand on high profitability in cutting operations has led to a variety of requirements for high performance tool coatings. Nanostructured coatings have shown most promising results in this connection. High oxidation resistance, hot hardness, and loW friction are just a few benefits that these coatings offer. The deposition of nanostructured coatings is only possible within a small deposition process window. Most cutting tool surfaces are complex shaped and include, for instance, small corner radii at the cutting edge or chip breakers. The local process window and the deposition parameters must be adapted to the actual shape of the cutting tools in order to obtain a hard nanocomposite coating with adequate adhesion properties. Finally, the performance of these coatings has been studied in machining tests. [source]