Relationship between secondary dendrite arm spacing and local solidification time of 30Cr2Ni4MoV alloy at slow cooling rates

2018 ◽  
Vol 25 (8) ◽  
pp. 821-829
Author(s):  
Jing Zhao ◽  
Hong-gang Zhong ◽  
Ke Han ◽  
Ren-xing Li ◽  
Zhi-shuai Xu ◽  
...  
Keyword(s):  
Solidification Time ◽  
Local Solidification Time ◽  
Slow Cooling ◽  
Cooling Rates ◽  
Secondary Dendrite Arm Spacing ◽  
Dendrite Arm Spacing

Dendritic and eutectic growth of Sn–0.5 wt.%Cu solders with low alloying Al levels

2018 ◽  
Vol 233 (9) ◽  
pp. 1733-1737 ◽  
Author(s):  
Thiago Soares Lima ◽  
Bismarck Luiz Silva ◽  
Amauri Garcia ◽  
Noé Cheung ◽  
José Eduardo Spinelli
Keyword(s):  
Eutectic Growth ◽  
Al Alloys ◽  
Thermal Parameters ◽  
Thermal Gradients ◽  
Dendritic Spacing ◽  
Cooling Rates ◽  
Secondary Dendrite Arm Spacing ◽  
Al Content ◽  
Dendrite Arm Spacing ◽  
The Matrix

The dependences of microstructures on the solidification thermal parameters of Sn–0.5 wt.%Cu, Sn–0.5 wt.%Cu–0.05 wt.%Al, and Sn–0.5 wt.%Cu–0.1 wt.%Al alloys are examined. Ranges of sizes and morphologies of microstructural phases have been quantitatively assessed due to the broad spectra of cooling rates and thermal gradients associated with the experiments. Various types of growth relations are proposed to represent the microstructural progresses. Al addition does not change either the matrix primary dendritic spacing or the spacing between Cu6Sn5 particles. However, it is shown that the secondary dendrite arm spacing, λ2, is greatly affected, increasing with the increase in the Al content. Both globular-type and fibrous-type morphologies typify the Cu6Sn5 intermetallics located in interdendritic zones.

Effects of Solidification Parameters on SDAS of A357 Alloy

2008 ◽  
Vol 51 ◽  
pp. 85-92 ◽  
Author(s):  
Juan He ◽  
Jian Min Zeng ◽  
Along Yan
Keyword(s):  
Cooling Rate ◽  
Solidification Time ◽  
Local Solidification Time ◽  
A357 Alloy ◽  
Solidification Condition ◽  
Alloy Casting ◽  
Furan Resin ◽  
Solidification Parameters ◽  
Relationship Of ◽  
The Relationship

In this investigation, experiments were carried out to study the relationship of solidification parameters and the secondary dendrite arm spacing (SDAS) in A357 alloy casting with various thicknesses under the same solidification condition. The results show that the cooling rate decreases as the thickness of specimens increases, the local solidification time increased, and SDAS increased. The relationships between the SDAS and cooling rate and local solidification time under the condition of furan resin self-hardening sand casting were obtained: SDAS = 20.8 tf 0.3, SDAS = 69.34 v -0.3. The mechanical properties have some linear relations with SDAS of A357 alloy after aging heat treatment. The correlations can be expressed: UTS=410.4-0.8SDAS and El%=7.9-0.05SDAS.

scholarly journals Minimizing Residual Stress in Brazed Joints by Optimizing the Brazing Thermal Profile

2020 ◽  
Author(s):  
Ben Mann ◽  
Kurtis Ford ◽  
Mike Neilsen ◽  
Dan Kammler
Keyword(s):  
Elastic Material ◽  
Curie Point ◽  
Thermal Strain ◽  
Optimization Techniques ◽  
Filler Materials ◽  
Thermal Profile ◽  
Slow Cooling ◽  
Element Analysis ◽  
Material Models ◽  
Cooling Rates

Abstract Ceramic to metal brazing is a common bonding process used in many advanced systems such as automotive engines, aircraft engines, and electronics. In this study, we use optimization techniques and finite element analysis utilizing viscoplastic and thermo-elastic material models to find an optimum thermal profile for a Kovar® washer bonded to an alumina button that is typical of a tension pull test. Several active braze filler materials are included in this work. Cooling rates, annealing times, aging, and thermal profile shapes are related to specific material behaviors. Viscoplastic material models are used to represent the creep and plasticity behavior in the Kovar® and braze materials while a thermo-elastic material model is used on the alumina. The Kovar® is particularly interesting because it has a Curie point at 435°C that creates a nonlinearity in its thermal strain and stiffness profiles. This complex behavior incentivizes the optimizer to maximize the stress above the Curie point with a fast cooling rate and then favors slow cooling rates below the Curie point to anneal the material. It is assumed that if failure occurs in these joints, it will occur in the ceramic material. Consequently, the maximum principle stress of the ceramic is minimized in the objective function. Specific details of the stress state are considered and discussed.

scholarly journals Effects of Au and Ge Additions on the Microstructures and Properties of Ag-1.5Cu-0.1Y Alloys

Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 123
Author(s):  
Desheng Zhang ◽  
Qin Zhang ◽  
Sida Li ◽  
Hongying Yang
Keyword(s):  
Corrosion Resistance ◽  
Alloying Elements ◽  
Strongly Correlated ◽  
Experimental Basis ◽  
Secondary Dendrite Arm Spacing ◽  
Dendrite Arm Spacing ◽  
Better Than

The application of silver is seriously affected by its tendency to oxidize and corrode. Therefore, the addition of proper alloying elements to silver-based alloys to achieve better properties has become a hot topic at present. In this current study, the effects of the addition of the two elements Au and Ge on the microstructures and properties of Ag-1.5Cu-0.1Y alloys were investigated. The results showed that the microstructures were refined and the second dendrite was shortened in the Ag-1.5Cu-0.1Y alloys with the addition of Au and Ge. Adding Au enhanced the corrosion resistance of the Ag-1.5Cu-0.1Y alloys. Furthermore, the corrosion resistance of the Ag-1.5Cu-0.1Y alloys with the addition of both Ge and Au was better than that of the alloy samples with Au added alone. The best corrosion resistance of the Ag-1.5Cu-0.1Y alloys was achieved by adding 1.0 wt.% Au and 1.0 wt.% Ge. The microhardness was enhanced by the addition of Au and Ge, and was strongly correlated with the secondary dendrite arm spacing (λ2) of the Ag-1.5Cu-0.1Y alloys. In addition, the Au addition could improve the conductivity of the Ag-1.5Cu-0.1Y alloy; however, Ge had little effect on the conductivity of the alloy samples. This work provides an experimental basis for the design of better performing silver-based alloys.

scholarly journals Predicting Secondary-Dendrite Arm Spacing of the Al-4.5wt%Cu Alloy During Unidirectional Solidification

2016 ◽  
Vol 20 (1) ◽  
pp. 68-75 ◽  
Author(s):  
Alexandre Furtado Ferreira ◽  
José Adilson de Castro ◽  
Leonardo de Olivé Ferreira
Keyword(s):  
Unidirectional Solidification ◽  
Secondary Dendrite Arm Spacing ◽  
Dendrite Arm Spacing ◽  
Cu Alloy
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