Rapid solidification of metals and alloys pdf

Specimens for Hardness of the resulting ribbons was electron microscopy were prepared HV but the conventional alloy and micrographs were taken using rods had the lowest hardness about 55 JOEL- electron microscope. X-ray HV. The glass slide in a Rigaku X-ray peaks were corresponding to the pure diffractometry. Hardness the ASTM values for pure aluminum measurements were made with a metal. Melt-spinning was carried out using different orifice sizes of the Results and Discussion: crucibles and different nozzle to The aluminum—magnesium wheel gaps.

The conditions in which alloy used in this investigation was a produced the best ribbons were at commercial alloy containing 2. All the only. However, the X-ray patterns revealed 3- The thermal analysis shows hat that peaks corresponding to the the weight gain is lower for the second phase were reached their ribbons as compared to the maximum intensity when the melt- aluminum alloy rods.

It seems, also References: that the formation of the second phase 1- J. Schaffer, A. Saxena, S. Sanders, S. The 2- W. Bolton, Engineering Materials formation of this phase was revealed Technology, Third Edition, Butter further by electron microscope Worth- Heinemann, Topics addressed include treatments of manufactured parts, surface characterization, and the effects of surface treatments on mechanical behavior.

Many different perspectives are covered, including design aspects, technologies, materials and. Additive Manufacturing Applications for Metals and Composites. ASM Desk Editions. Edited by. Joseph R. Davis Joseph R. This Site.

Google Scholar. ASM International. Publication date:. Book Chapter. Results and discussion microstructure by means of rapid solidification process is one of the highly potential approaches to improve the mechanical Fig. However, there are few reports about rapidly tionally casting alloy and rapidly solidified alloy. Three phases, solidified magnesium alloys [8].

The current research aims at i. This may be attributed to the effect of internal strain accommodated in the microstructure. The E-mail address: hfzhang imr. Cai et al. X-ray diffraction patterns: a conventional casting alloy and b rapidly solidified alloy. In addition, the microstructure is refined for the rapidly solid- ified alloy. Al8 Mn5 phase is smaller and more homogeneously distributed in the rapidly solidi- fied alloy, while aggregates in the conventionally casting alloy Fig.

A typical macrograph of the conventional alloy is shown in Fig. However, the secondary dendrite arm spacing SDAS is diffi- cult to measure in the casting because its grains are globular or cellular in rapidly solidified alloys. It is known that SDAS depends upon the solidification time. Table 2 shows as the cool- ing rate increases, the grain size and secondary dendrite arm spacing decrease correspondingly, but the volume fraction of the divorced eutectic increases.

Grain refinement is one of the important practices to improve the mechanical properties of castings [9]. It is an essential and fundamental approach since grain size significantly influences the mechanical properties of the castings. It is well known that Fig. Microstructure of the alloys: a conventional casting alloy and b rapidly the nucleation depends on the number and size of clusters in the solidified AZ91HP alloy.

Macrostructure of conventional casting AZ91HP alloy. Thus it can be seen that effective nucleation ratio or restraint of growth rate will result in grain refinement. Copper mould can produce higher super cooling than conven- tional casting [10].

The results described above show that the rapid solidification can refine microstructure. Deterioration in ductility may be caused by a tendency Fig. Optical micrographs of a conventionally casting alloy; b rapidly solid- towards the formation of microporosity [11] and the high pro- ified alloy glycerol nitric acid etchant. A typical eutectic structure of conventionally in Fig. As illustrated in Fig. These parti- in rapidly solidified alloys Fig.

Ductility at room tem- cles contribute to enhancement of the material hardness [14].