Solid State Phenomena
Vol. 127
Vol. 127
Solid State Phenomena
Vols. 124-126
Vols. 124-126
Solid State Phenomena
Vols. 121-123
Vols. 121-123
Solid State Phenomena
Vol. 120
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Solid State Phenomena
Vol. 119
Vol. 119
Solid State Phenomena
Vol. 118
Vol. 118
Solid State Phenomena
Vols. 116-117
Vols. 116-117
Solid State Phenomena
Vol. 115
Vol. 115
Solid State Phenomena
Vol. 114
Vol. 114
Solid State Phenomena
Vol. 113
Vol. 113
Solid State Phenomena
Vol. 112
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Solid State Phenomena
Vol. 111
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Solid State Phenomena
Vol. 110
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Solid State Phenomena Vols. 116-117
Paper Title Page
Abstract: Various processing methods exist for applying agitation to a molten metal during
solidification to obtain metal slurries suitable for semi-solid metal processing. . In this paper, a new
technique to achieve semi-solid metal structure using agitation during solidification is reported. The
technique applies a new medium and means to efficiently create semi-solid metal structures. The
results of a systematic study showing the feasibility and the necessary conditions to achieve the
structure are discussed.
366
Abstract: New manufacturing methods for metal matrix composites (MMC) are developed.
Thermally sprayed metal coatings on reinforcement-fabrics are used as preforms (prepregs) for an
advanced thixoforging process. The semi-solid forming and simultaneous infiltration in short cycle
times offer the possibility to realize complex near net-shape geometries and reduces fiber damage to a
minimum.
370
Abstract: Processing of light-metals in semi-solid state offers some advantages regarding process
temperatures, handling of the material, but also the resulting micro-structure of the final component.
Reinforcement of light-metal components with fibers or particles can be applied in order to increase
elastic modulus and yield strength of the material as well as its wear resistance. But, the
manufacturing of metal matrix composites by thixoforging requires the supply of raw material that
shows thixotropic behavior at processing temperature and that contains a definite volume fraction of
well distributed reinforcement phase. In this work, an arc wire spray process is applied for the
manufacturing of semi-finished parts by coating of long-fiber fabrics and by deposition of ceramic
particle containing billets. The process technique is described and the suitability of thermally sprayed
matrix material for semi-solid processing is verified.
375
Abstract: A356 was cast into the strip by the semisolid strip casting using an unequal diameter twin
roll caster. This process was one of the rheocasting. The semisolid slurry was made by a cooling slope.
Solid fraction was about 5%. The casting speed was 20 m/min, and the thickness was 4.4 mm. The
as-cast strip could be cold rolled down to 1 mm. The result of tension test of 1mm-thickness-T4
heat-treated strip was as below. Tensile stress was 223 MPa, 0.2 proof stress was 123 MPa and
elongation was 21.8%. Deep drawing could be operated to 1 mm-thickness T4 sheet, and L.D.R was
attained to 2.0. In some condition, 180 degrees bending could be operated without crack at outer
surface. These results mean that semisolid roll cast A356 strip may be able to use for press forming.
379
Abstract: The thixoforming processes join the advantages of conventional forming technologies as
forging and casting in respect of the mechanical properties and the practicable geometries. Within the
framework of the Collaborative Research Centre 289 at the RWTH Aachen University intensive
investigations on semi-solid processing with some steel grades have been running. For this purpose an
automated thixoforging plant (thixo-cell) has been developed in a closed cooperation with several
industrial partners. With this equipment multi material demonstrator components have been
successfully produced by thixojoining using semi-solid X210CrW12 tool steel.
383
Abstract: Bühler has developed an economical way to produce high quality structural parts using
conventional die casting equipment.
387
Abstract: Ultrasonic vibration was applied to the surface of AZ91D/CNF slurries in order to
homogeneously disperse the reinforcement through the semi-solid matrix, and eliminate the clusters
of nano-fibres originated during previous processes. The method utilized to produce the slurry was a
modified compocasting process that generates semi-solid magnesium alloy using an inclined cooling
plate and mechanical stirring. The CNF reinforcement was added in quantities varying from 1 to
3vol% and different vibration times and amplitudes were applied to the slurries under isothermal
conditions. Macro and microstructure combined analysis showed the occurrence of grain refinement
in the whole ingot for higher wave amplitudes at shorter times, while for lower amplitudes longer
times up to 10min. were required. Vibration times over 10min were not significant to further improve
the results and times up to 4min did not seem to provide any result whatsoever. The best results,
however, were obtained for 16 and 18μm amplitudes. Discontinuous application of ultrasound seems
to produce better results than continuous vibration. The dispersion of reinforcement seems to occur
by the smash of CNF clusters due to the movement of the solid fraction present in the Mg alloy slurry,
and by cavitation, responsible also for some microporosity present in the microstructures.
392
Abstract: A method for joining metals in the semisolid state is presented. A model alloy Sn-15%Pb
was used to demonstrate the concept. By presented process, dendritic microstructure of the weld
zone can be avoided. Moreover, near-weld zone of the cold worked substrates which is affected by
heat would have a globular structure due to a thermomechanical treatment. The two substrates were
heated up locally in the joint line to the semisolid temperature range. At this point a stirrer was
introduced into the weld seam in order to mix the two sides into a single uniform joint. Localized
mechanical properties of different zones were examined using Shear Punch Test (SPT), showing a
good strength in the weld zone and thermomechanically affected zone.
397
Abstract: The continuous rheoconversion process (CRP) is a novel slurry-on-demand process that
was developed at MPI/WPI in 2002. The process is based on a passive liquid mixing technique in
which the nucleation and growth of the primary phase are controlled using a specially designed
“reactor”. The reactor provides heat extraction, copious nucleation, and forced convection during
the initial stage of solidification, thus leading to the formation of globular structures. This paper
presents our recent work on the scale-up of the CRP for industrial applications. Specifically, we
demonstrate an important application of the CRP to low temperature (low fraction solid) HPDC. In
Part I of this paper, we present salient results on microstructural characterization of CRP processed
castings vs. conventional die castings.
402
Abstract: Novel semisolid casting method to produce bulk metal ingots with homogeneous fine-grained
structure is proposed. In the method, the fine-grained particles are subjected to partial melting and
compacting. As a result, the ingot structure is constituted mainly by fine-grained particles bonded
by inerlayers of solidified melt.
406