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| 2. |
- Glasbey, JC, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 5. |
- Padmavathi, C., et al.
(författare)
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Effect of pulsed Nd : YAG laser melting treatment on microstructural and corrosion behaviour of AZ91C Mg alloy
- 2006
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Ingår i: Materials Science and Technology. - 0267-0836 .- 1743-2847. ; 22:5, s. 583-589
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, an attempt was made to improve the corrosion resistance and microhardness of a cast magnesium-aluminium-zinc alloy by laser surface melting. A 400 W pulsed Nd:YAG laser was used to melt and rapidly quench the surface of the cast AZ91C alloy to improve the corrosion resistance. This was evaluated using potentiodynamic polarisation and EIS studies. The microstructure of the melt pool was examined using optical microscopy and scanning electron microscopy (SEM) along with energy dispersive spectroscopy (EDS), X-ray diffraction studies (XRD) and X-ray fluorescence (XRF). The work revealed that laser melting improves the corrosion resistance of as cast AZ91C alloy because of its fine microstructure and extensive solubility of aluminium in eutectic (β phase). The microhardness of the laser surface melted layer was also increased from 74 HV to 99-124 HV. © 2006 Institute of Materials, Minerals and Mining.
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| 6. |
- Padmavathi, C., et al.
(författare)
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Improving wear resistance of cast AZ91C magnesium alloy by surface melting techniques
- 2006
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Ingår i: Transactions of the Indian Institute of Metals. - 0019-493X. ; 59:1, s. 99-106
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Tidskriftsartikel (refereegranskat)abstract
- AZ91C cast magnesium alloy is an excellent candidate for automotive industries due to its low density. However, AZ91C alloy is not considered as suitable alloy for mechanical applications due to its low wear resistance property. In this present study, surface melting techniques were adopted to improve the wear resistance of AZ91C alloy. Gas tungsten arc with pulsing mode and pulsed laser surface melting techniques were carried out. The wear properties were evaluated from the pin-on-disc wear testing. The hardness values of the surface melted layers increased as compared with alloy in cast condition. The wear results showed that the surface melting processes has improved the wear resistance as compared with as cast. The improvement in wear resistance may be attributed due to grain refinement imparted by surface melting techniques. The wear rates of the alloy depend on hardness of alloy. The wear surface and wear debris were analyzed with optical microscopy, SEM along with EDS analysis and XRD studies for determining the mode of wear and wear mechanism. The worn surface analysis of surface melted samples were very smooth and granular peeling was hardly observed as compared to the generation of loose debris in the case of as cast alloy.
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- Bandyopadhyay, S., et al.
(författare)
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Geometrical features and metallurgical characteristics of Nd : YAG laser drilled holes in thick IN718 and Ti-6Al-4V sheets
- 2002
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Ingår i: Journal of Materials Processing Technology. - 0924-0136 .- 1873-4774. ; 127:1, s. 83-95
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Tidskriftsartikel (refereegranskat)abstract
- Laser drilling is increasingly becoming the method of choice for precision drilling of a variety of components, particularly in the aircraft industry. Notwithstanding the current level of acceptance of laser drilling in the aerospace industry, a number of defects such as spatter, recast and taper are associated with laser drilled holes and elimination of these defects is the subject of intense research. The present paper deals with Nd:YAG laser drilling of 4 and 8mm thick sections of IN718 and Ti-6Al-4V materials. The influence of type of material and its thickness, as well as parametric impact of key process variables like pulse frequency and pulse energy, have been determined. In the course of this study, relevant geometrical features of the drilled holes, like hole diameter and taper angle, have been comprehensively investigated. In addition, all metallurgical characteristics of interest, viz extent and nature of spatter, recast and heat-affected zone, have been evaluated. Effort has also been made to obtain some insights into the evolution of a through-thickness hole during laser percussion drilling of thick sections by careful experimentation involving monitoring the progression of the drilled hole with increasing number of laser pulses. Issues pertaining to variation of taper with depth of hole, change in crater depth with progressive drilling and specific energy consumption are also discussed. © 2002 Elsevier Science B.V. All rights reserved.
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