Laser Engineered Net Shaping Process for 316L/15% Nickel Coated Titanium Carbide Metal Matrix Composite

Author(s):  
R. S. Amano ◽  
S. Marek ◽  
B. F. Schultz ◽  
P. K. Rohatgi

This paper presents the investigation of the macrostructure, microstructure, and solidification structure of a 316L/15% nickel coated TiC metal matrix composite produced by the laser engineered net shaping (LENS™) process. The focus of this work was to (1) identify the solidification structure and to estimate growth/cooling rates at the solid/liquid interface, (2) identify and quantify discontinuities in the build structure, and (3) examine the effect of solidification and thermal history on the sample microstructure to further the understanding of the LENS process. A Numerical method was also developed to examine the influence of material type and LENS™ process parameters on the forming of the specific microstructures from thermodynamics and fluid dynamics point of view. Samples of 316L stainless steel were examined, microstructures of samples were used to estimate the corresponding cooling rate, and the cooling rate was compared with the results of numerical modeling. The computational results show reasonable agreement with experimentally determined cooling rate.

Author(s):  
Z. Xu ◽  
R. S. Amano ◽  
J. M. Lucci ◽  
Steven Gerard Marek ◽  
Pradeep Rohatgi ◽  
...  

The objectives of this work are to study Laser Engineered Net Shaping (LENS™) produced materials and identify the microstructures. Numerical method was used to examine the influence of materials’ type and LENS™ process parameters on the forming of the specific microstructures from thermodynamics and fluid dynamics point of view. Samples of 316L stainless steel were examined, microstructures of samples were used to estimate the corresponding cooling rate, and the cooling rate was compared with the results of three different level of simplified models.


Author(s):  
Zhenyu Xu ◽  
R. S. Amano ◽  
Pradeep Rohatgi

The objectives of this work are to study Laser Engineered Net Shaping (LENS™) produced materials and identify the microstructures. Numerical method was used to examine the influence of materials’ type and LENS™ process parameters on the forming of the specific microstructures from thermodynamics and fluid dynamics point of view. Samples of 4140 low alloy steel and 316L stainless steel were examined, microstructures of samples were used to estimate the corresponding cooling rate, and the cooling rate was compared with the numerical results.


2014 ◽  
Vol 217-218 ◽  
pp. 265-273 ◽  
Author(s):  
Antonio de Pádua Lima Filho ◽  
Rafael Shoiti Ikeda ◽  
Tales Paschoalino de Castro ◽  
Ricardo Luiz Pugina Filho

Continuous metal matrix composite strip casting (MMCS-ing) composed of six 0.3-mm diameter annealed bare copper wires in a eutectic SnPb matrix was manufactured by a two-roll melt dragged processing (TRMD-ing) method at a rate of 0.3 m/s. The wires were dragged through a semisolid pool with a fibre contact time of approximately 0.2 s. The required gap between rolls to thixoforge the semisolid material around the wire filaments was approximately 1.4 mm. A successful continuous composite strip casting was achieved with a notably good degree of wire alignment. No cracks were observed at the copper wire/matrix interface. However, regions of porosity occurred in the matrix; their possible formation mechanisms are discussed. The solidification structure of the matrix was analysed, and the analysis results indicated the formation of small globular grains measuring approximately 3 μm in diameter. The specimens were evaluated for their tensile properties and compared with the rule of mixtures. The surface fracture analysis indicated a good matrix/fibre union. MMCS-ing is an economically viable process and has significant advantages over other metal matrix composite (MMC) fabrication methods.


Author(s):  
M. G. Burke ◽  
M. N. Gungor ◽  
P. K. Liaw

Aluminum-based metal matrix composites offer unique combinations of high specific strength and high stiffness. The improvement in strength and stiffness is related to the particulate reinforcement and the particular matrix alloy chosen. In this way, the metal matrix composite can be tailored for specific materials applications. The microstructural characterization of metal matrix composites is thus important in the development of these materials. In this study, the structure of a p/m 2014-SiC particulate metal matrix composite has been examined after extrusion and tensile deformation.Thin-foil specimens of the 2014-20 vol.% SiCp metal matrix composite were prepared by dimpling to approximately 35 μm prior to ion-milling using a Gatan Dual Ion Mill equipped with a cold stage. These samples were then examined in a Philips 400T TEM/STEM operated at 120 kV. Two material conditions were evaluated: after extrusion (80:1); and after tensile deformation at 250°C.


2019 ◽  
Vol 13 (4) ◽  
pp. 5804-5817
Author(s):  
Ibrahim Sabry

It is expected that the demand for Metal Matrix Composite (MMCs) will increase in these applications in the aerospace and automotive industries sectors, strengthened AMC has different advantages over monolithic aluminium alloy as it has characteristics between matrix metal and reinforcement particles.  However, adequate joining technique, which is important for structural materials, has not been established for (MMCs) yet. Conventional fusion welding is difficult because of the irregular redistribution or reinforcement particles.  Also, the reaction between reinforcement particles and aluminium matrix as weld defects such as porosity in the fusion zone make fusion welding more difficult. The aim of this work was to show friction stir welding (FSW) feasibility for entering Al 6061/5 to Al 6061/18 wt. % SiCp composites has been produced by using stir casting technique. SiCp is added as reinforcement in to Aluminium alloy (Al 6061) for preparing metal matrix composite. This method is less expensive and very effective. Different rotational speeds,1000 and 1800 rpm and traverse speed 10 mm \ min was examined. Specimen composite plates having thick 10 mm were FS welded successfully. A high-speed steel (HSS) cylindrical instrument with conical pin form was used for FSW. The outcome revealed that the ultimate tensile strength of the welded joint (Al 6061/18 wt. %) was 195 MPa at rotation speed 1800 rpm, the outcome revealed that the ultimate tensile strength of the welded joint (Al 6061/18 wt.%) was 165 MPa at rotation speed 1000 rpm, that was very near to the composite matrix as-cast strength. The research of microstructure showed the reason for increased joint strength and microhardness. The microstructural study showed the reason (4 %) for higher joint strength and microhardness.  due to Significant   of SiCp close to the boundary of the dynamically recrystallized and thermo mechanically affected zone (TMAZ) was observed through rotation speed 1800 rpm. The friction stir welded ultimate tensile strength Decreases as the volume fraction increases of SiCp (18 wt.%).


2013 ◽  
Vol 58 (3) ◽  
pp. 659-662 ◽  
Author(s):  
K. Gawdzińska

Abstract In this paper it is stated, that a set of quality features of metal matrix composite castings differs from the same set for castings of classic materials, although some features are common for both of these material groups. These features (pertaining to a set of quality characteristics of composite castings) have been named as specific, they have not been determined yet and a description of material quality should be performed (according to the qualitology) on a principle of description of quality characteristics of this product. Therefore, this set of features has been determined. It was proposed to add the following characteristics to the set of specific features of composite castings quality: matrix material, reinforcement material, binding between components and porosity of the composite casting. In this set a sub-set of quality characteristics of composite castings was also determined.


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