scispace - formally typeset


Spray forming

About: Spray forming is a(n) research topic. Over the lifetime, 1153 publication(s) have been published within this topic receiving 12869 citation(s). The topic is also known as: spray casting & spray deposition.

More filters
02 Aug 1972
Abstract: Metal matrix composites consist of a metal or an alloy as the continuous matrix and a reinforcement that can be particle, short fiber or whisker, or continuous fiber. In this chapter, we first describe important techniques to process metal matrix composites, then we describe the interface region and its characteristics, properties of different metal matrix composites, and finally, we summarize different applications of metal matrix composites.

261 citations

Journal ArticleDOI
Abstract: A mathematical representation has been developed and computed results are presented describing the spreading of droplets impacting onto a solid substrate. Problems of this type are of major practical interest in plasma spraying (PS) and in spray forming (SF) operations. While the present study was confined to the fluid flow aspects of the process, information has been generated on both the final splat dimensions and on the time required to complete the spreading process. Through this treatment, it is possible to relate these quantities (the splat size and the spreading time) to the operating conditions,i.e., droplet size and droplet velocity, and material properties. The theoretical predictions were found to be in good agreement with both Madejski’s asymptotic solution[17] and with available experimental results. For typical SF conditions (droplet sizes in the 100-µm range and droplet velocities in the 100 m/s range), the spreading times were of the order of microseconds,i.e., significantly shorter than the estimated solidification time.

249 citations

Journal ArticleDOI
Abstract: A mathematical representation has been developed, and computed results are presented describing the spreading and solidification of droplets impacting onto a solid substrate. This impingement is of major practical interest in plasma spraying and spray forming operations. Experiments in which molten metal drops were made to impinge onto a substrate were used to test the model. High-speed videography was used to record the spreading process, which typically took a few milliseconds for the experimental conditions employed. A comparison was made of the theoretical predictions with the experimental measurements; these were found to be in very good agreement, suggesting that the theoretical treatment of the model is sound. These calculations permit the prediction of the time and extent of the spreading process, the solidification rate, and the effect of process parameters, such as droplet size, droplet velocity, superheat, and material properties, provided that a value of the thermal contact coefficient is known. The most important finding of the modeling work is that for large droplets (∼5-mm diameter) with low impinging velocities (∼2 m/s), spreading and solidification appear to take place at comparable rates; in contrast, for small (∼100−µm diameter) particles impacting at a high velocity (∼100 m/s), the time scale for spreading appears to be shorter than the time scale for solidification (within the range of parameters of this study.)

163 citations

Journal ArticleDOI
Abstract: In order to predict gas and droplet velocities, droplet temperature, and fractional solidification with flight distance during spray forming, the Newtonian heat transfer formulation has been coupled with the classical heterogeneous nucleation and the specific solidification process. It has been demonstrated that the thermal profile of the droplet in flight is significantly affected by process parameters such as droplet size, initial gas velocity, undercooling, and superheat. With increasing droplet size or initial gas velocity, the onset and completion of solidification are shifted to greater flight distances and the solidification process also extends over a wider range of flight distances. It has been found that the corresponding solid fractions formed during recalesced, segregated, and eutectic solidifications are linearly related to the degree of undercooling and that those solid fractions are insensitive to droplet size, initial gas velocity and superheat.

156 citations

Journal ArticleDOI
Abstract: Metal matrix composites have been available in certain forms for at least two decades, e.g. boron fibre reinforced aluminium and various dispersed phase alloys and cermets. Recently, a range of alumina and silicon carbide fibres, whiskers, and particles with diameters <20 μm have become available. The possibilities of incorporating these materials into metals to improve stiffness, wear resistance, and elevated temperature strength without incurring weight penalties have attracted the attention of design engineers in the aerospace and automobile industries. The aim of the present paper is to outline the manufacturing processes for such composites, in particular those based upon liquid metal technology, e.g. squeeze casting and spray forming. Some of the mechanical and physical properties which have been determined for these materials are described. An analysis of how matrix alloy selection may influence tensile and fracture behaviour of short fibre and particle reinforced composites is attempted.MS...

134 citations

Trending Questions (1)
Network Information
Related Topics (5)

171.8K papers, 1.7M citations

84% related

148.6K papers, 2.2M citations

83% related
Grain boundary

70.1K papers, 1.5M citations

81% related
Ultimate tensile strength

129.2K papers, 2.1M citations

76% related
Fracture mechanics

58.3K papers, 1.3M citations

76% related
No. of papers in the topic in previous years