Pub Date : 2002-10-18DOI: 10.1080/0898150021000054566
J. Lawrence
It is quite possible to bring about changes in the wettability characteristics of a two-stage ceramic tile grout by means of high power diode laser (HPDL) surface treatment. Such changes manifest themselves as a reduction in the contact angle, , and are due to the HPDL inducing changes which reduce the surface roughness, increase the surface O 2 content and increasing the polar component of the surface energy. What is more, HPDL treatment of the two-stage ceramic tile grout surface was found to effect an improvement in the bonding characteristics by increasing the work of adhesion, W ad . Along with wettability experiments carried out with selected liquid-metals, an electronic approach was used to identify the bonding characteristics of the two-stage ceramic tile grout before and after HPDL. It is thought that HPDL induced changes to the two-stage ceramic tile grout produced a surface with a reduced bandgap energy which consequently increased W ad by increasing the electron transfer at the metal-oxide i...
{"title":"An analysis of the bonding mechanisms active in a high power diode laser generated two-stage ceramic tile grout","authors":"J. Lawrence","doi":"10.1080/0898150021000054566","DOIUrl":"https://doi.org/10.1080/0898150021000054566","url":null,"abstract":"It is quite possible to bring about changes in the wettability characteristics of a two-stage ceramic tile grout by means of high power diode laser (HPDL) surface treatment. Such changes manifest themselves as a reduction in the contact angle, , and are due to the HPDL inducing changes which reduce the surface roughness, increase the surface O 2 content and increasing the polar component of the surface energy. What is more, HPDL treatment of the two-stage ceramic tile grout surface was found to effect an improvement in the bonding characteristics by increasing the work of adhesion, W ad . Along with wettability experiments carried out with selected liquid-metals, an electronic approach was used to identify the bonding characteristics of the two-stage ceramic tile grout before and after HPDL. It is thought that HPDL induced changes to the two-stage ceramic tile grout produced a surface with a reduced bandgap energy which consequently increased W ad by increasing the electron transfer at the metal-oxide i...","PeriodicalId":49918,"journal":{"name":"Lasers in Engineering","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2002-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80182771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1080/0898150021000054557
M. Kozłowski, J. Marciak-kozlowska
In this article, the effects of zero-point energy (ZPE) on the heat transport induced by ultra-short laser pulses are investigated. It is shown that the existence of the zero-point energy in a physical vacuum influences the heat transport on an atomic level. The interaction of the building blocks of matter-atoms with the zero-point fields (ZPFs), which generate the ZPE guarantees the stability of matter. The interaction of the ultra-short laser pulses ( j t ¨ 1 as) with matter can be used as a source of information on the ZPF.
{"title":"Zero point field (ZPF) effects in the interaction of the ultra-short laser pulses with matter","authors":"M. Kozłowski, J. Marciak-kozlowska","doi":"10.1080/0898150021000054557","DOIUrl":"https://doi.org/10.1080/0898150021000054557","url":null,"abstract":"In this article, the effects of zero-point energy (ZPE) on the heat transport induced by ultra-short laser pulses are investigated. It is shown that the existence of the zero-point energy in a physical vacuum influences the heat transport on an atomic level. The interaction of the building blocks of matter-atoms with the zero-point fields (ZPFs), which generate the ZPE guarantees the stability of matter. The interaction of the ultra-short laser pulses ( j t ¨ 1 as) with matter can be used as a source of information on the ZPF.","PeriodicalId":49918,"journal":{"name":"Lasers in Engineering","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81800096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1080/08981500220151783
B. Majumdar, R. Galun, B. Mordike, A. Weisheit
The surface melting characteristics of AZ91 alloy is investigated using excimer laser (pulses of length 45 ns) under ambient conditions and also a N 2 environment. Experiments are carried out on overlapping spots with close interval. The melt layer hardness for treatment in air is increased to 162 VHN as compared to 73 VHN for the untreated alloy (AZ91 T4 condition), whereas the hardness of the sample treated in an N 2 atmosphere is 116 VHN. A transmission electron microscopy study reveals that the laser treated surface contains nanoparticles of oxide and nitride embedded in the submicron grains of the Mg solid solution. This is responsible for the observed high hardness which gives rise to the improved abrasive resistance. We propose a model to describe the formation of nanoparticles during the laser treatment.
{"title":"Formation of embedded nanoparticles in an excimer laser treated Mg alloy surface","authors":"B. Majumdar, R. Galun, B. Mordike, A. Weisheit","doi":"10.1080/08981500220151783","DOIUrl":"https://doi.org/10.1080/08981500220151783","url":null,"abstract":"The surface melting characteristics of AZ91 alloy is investigated using excimer laser (pulses of length 45 ns) under ambient conditions and also a N 2 environment. Experiments are carried out on overlapping spots with close interval. The melt layer hardness for treatment in air is increased to 162 VHN as compared to 73 VHN for the untreated alloy (AZ91 T4 condition), whereas the hardness of the sample treated in an N 2 atmosphere is 116 VHN. A transmission electron microscopy study reveals that the laser treated surface contains nanoparticles of oxide and nitride embedded in the submicron grains of the Mg solid solution. This is responsible for the observed high hardness which gives rise to the improved abrasive resistance. We propose a model to describe the formation of nanoparticles during the laser treatment.","PeriodicalId":49918,"journal":{"name":"Lasers in Engineering","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82548176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1080/0898150021000014092
B. Yilbas, M. Rashid
In this article CO 2 laser cutting of Incoloy 800 HT alloy is studied. The dross ejected from the kerf is monitored and the frequency of dross ejection correlated with the striation frequency. SEM microphotography and measurement of the surface roughness of the cut edges are carried out. International standards for thermal cutting are used to assess the quality of the cut edges. A statistical analysis employing a factorial analysis is carried out to determine the significance levels of the cutting speed, laser output intensity, thickness, and the pulse frequency of the laser beam for the waviness, out of flatness, and overall quality of the cut edges. It is found that the dross ejection frequency is directly related to the striation frequency. The results of SEM microphotography, surface roughness measurement, and the optical method for the striation frequency monitoring are found to be in good agreement. The overall quality of the cut edge improves within a certain range of pulsing frequency, which is ca...
{"title":"CO 2 laser cutting of Incoloy 800 HT alloy and its quality assessment","authors":"B. Yilbas, M. Rashid","doi":"10.1080/0898150021000014092","DOIUrl":"https://doi.org/10.1080/0898150021000014092","url":null,"abstract":"In this article CO 2 laser cutting of Incoloy 800 HT alloy is studied. The dross ejected from the kerf is monitored and the frequency of dross ejection correlated with the striation frequency. SEM microphotography and measurement of the surface roughness of the cut edges are carried out. International standards for thermal cutting are used to assess the quality of the cut edges. A statistical analysis employing a factorial analysis is carried out to determine the significance levels of the cutting speed, laser output intensity, thickness, and the pulse frequency of the laser beam for the waviness, out of flatness, and overall quality of the cut edges. It is found that the dross ejection frequency is directly related to the striation frequency. The results of SEM microphotography, surface roughness measurement, and the optical method for the striation frequency monitoring are found to be in good agreement. The overall quality of the cut edge improves within a certain range of pulsing frequency, which is ca...","PeriodicalId":49918,"journal":{"name":"Lasers in Engineering","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90603526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1080/0898150021000039284
J. Majumdar, I. Manna
Laser surface alloying involves tailoring the surface microstructure and composition by rapid melting, intermixing and solidification of a pre/co-deposited surface layer with a part of the underlying substrate. It is a potential method of enhancing hardness and wear resistance of engineering components. In the present study, a one-dimensional heat transfer model based on the explicit finite difference method has been developed to predict the thermal history (i.e., temperature profile, thermal gradient, cooling rate and solid-liquid interface velocity) and hence, the microstructure of the alloyed zone developed by laser surface alloying. The incident laser power and laser-matter interaction time are chosen as the main variables to study the effect of laser parameters on thermal history, and consequently, microstructure of the alloyed zone. The numerical calculations have been carried out for the model system of AISI 304 stainless steel laser surface alloyed with pre-deposited molybdenum. The predicted resu...
{"title":"A mathematical model to predict the thermal history and microstructure developed in laser surface alloying","authors":"J. Majumdar, I. Manna","doi":"10.1080/0898150021000039284","DOIUrl":"https://doi.org/10.1080/0898150021000039284","url":null,"abstract":"Laser surface alloying involves tailoring the surface microstructure and composition by rapid melting, intermixing and solidification of a pre/co-deposited surface layer with a part of the underlying substrate. It is a potential method of enhancing hardness and wear resistance of engineering components. In the present study, a one-dimensional heat transfer model based on the explicit finite difference method has been developed to predict the thermal history (i.e., temperature profile, thermal gradient, cooling rate and solid-liquid interface velocity) and hence, the microstructure of the alloyed zone developed by laser surface alloying. The incident laser power and laser-matter interaction time are chosen as the main variables to study the effect of laser parameters on thermal history, and consequently, microstructure of the alloyed zone. The numerical calculations have been carried out for the model system of AISI 304 stainless steel laser surface alloyed with pre-deposited molybdenum. The predicted resu...","PeriodicalId":49918,"journal":{"name":"Lasers in Engineering","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76539144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1080/08981500290022752
Y. Zamachtchikov, F. Breabăn, P. Vantomme, A. Deffontaine
{"title":"Method to evaluate residual stresses in the laser cutting process","authors":"Y. Zamachtchikov, F. Breabăn, P. Vantomme, A. Deffontaine","doi":"10.1080/08981500290022752","DOIUrl":"https://doi.org/10.1080/08981500290022752","url":null,"abstract":"","PeriodicalId":49918,"journal":{"name":"Lasers in Engineering","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88509220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1080/08981500220151756
J. Lawrence, Lin Li
By using a number of techniques and approaches certain differences between the beam interaction characteristics of CO 2 laser, a Nd:YAG laser, a high power diode laser (HPDL) and an excimer laser with a SiO 2 /Al 2 O 3 ceramic have been investigated. By employing a derivative of Beer-Lambert's law, the laser beam absorption lengths of the four lasers were calculated as 470 - 22 µm for the CO 2 laser, 195 - 12 µm for the Nd:YAG laser, 177 - 15 µm for the HPDL and 7.5 - 19 µm for the excimer laser. The fluence threshold values at which significant material removal occurs the CO 2 laser, Nd:YAG laser, HPDL and excimer laser were found to be 68, 128, 181 and 0.12 J cm m 2 , respectively. Absorptivity measurements revealed that there is no correlation between the actual absorptivity of the SiO 2 /Al 2 O 3 ceramic and the absorption length for each of the four lasers. The thermal loading values for the CO 2 laser, the, Nd:YAG laser, the HPDL and the excimer laser were determined as 2.57, 6.73, 9.83 and 22.24 kJ...
{"title":"On the differences between the beam interaction characteristics of CO 2, Nd:YAG, excimer and high power diode lasers with a SiO 2/Al 2O 3 ceramic","authors":"J. Lawrence, Lin Li","doi":"10.1080/08981500220151756","DOIUrl":"https://doi.org/10.1080/08981500220151756","url":null,"abstract":"By using a number of techniques and approaches certain differences between the beam interaction characteristics of CO 2 laser, a Nd:YAG laser, a high power diode laser (HPDL) and an excimer laser with a SiO 2 /Al 2 O 3 ceramic have been investigated. By employing a derivative of Beer-Lambert's law, the laser beam absorption lengths of the four lasers were calculated as 470 - 22 µm for the CO 2 laser, 195 - 12 µm for the Nd:YAG laser, 177 - 15 µm for the HPDL and 7.5 - 19 µm for the excimer laser. The fluence threshold values at which significant material removal occurs the CO 2 laser, Nd:YAG laser, HPDL and excimer laser were found to be 68, 128, 181 and 0.12 J cm m 2 , respectively. Absorptivity measurements revealed that there is no correlation between the actual absorptivity of the SiO 2 /Al 2 O 3 ceramic and the absorption length for each of the four lasers. The thermal loading values for the CO 2 laser, the, Nd:YAG laser, the HPDL and the excimer laser were determined as 2.57, 6.73, 9.83 and 22.24 kJ...","PeriodicalId":49918,"journal":{"name":"Lasers in Engineering","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82315791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1080/08981500290022761
N. Sivakumar, K. Venkatakrishnan, B. Ngoi
With the growing importance of micro machining, it has become important to characterise the profile of slot surfaces in order to understand the machining process in detail. In this paper, a novel optical layout adapting the concept of Mirau interferometry to polarization optics, in combination with instantaneous phase shifting interferometry, for measurement of slot surfaces is described. Experiments were carried out with this setup on a wafer surface with slot and the results were compared with that of a commercial surface profiler to demonstrate the applicability of the principle. The results obtained, were discussed with reference to the beam spot size, positioning of the object and the vertical resolution of the measurement setup, and compared with that of the commercial surface profiler.
{"title":"A novel technique for micro profiling of slots","authors":"N. Sivakumar, K. Venkatakrishnan, B. Ngoi","doi":"10.1080/08981500290022761","DOIUrl":"https://doi.org/10.1080/08981500290022761","url":null,"abstract":"With the growing importance of micro machining, it has become important to characterise the profile of slot surfaces in order to understand the machining process in detail. In this paper, a novel optical layout adapting the concept of Mirau interferometry to polarization optics, in combination with instantaneous phase shifting interferometry, for measurement of slot surfaces is described. Experiments were carried out with this setup on a wafer surface with slot and the results were compared with that of a commercial surface profiler to demonstrate the applicability of the principle. The results obtained, were discussed with reference to the beam spot size, positioning of the object and the vertical resolution of the measurement setup, and compared with that of the commercial surface profiler.","PeriodicalId":49918,"journal":{"name":"Lasers in Engineering","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76893257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1080/0898150021000014083
R. Kaul, P. Ganesh, M. O. Ittoop, A. Nath, Aniruddha Kumar, R. Bhatt, Arun Kumar
The dissimilar weld, a fuel clad tube (D9 alloy) and an end plug made of AISI 316M forms a part of the fuel pin in the 500 MW Indian Prototype Fast Breeder Reactor (PFBR). The present study aimed at the development of a crack resistant microstructure of the dissimilar weld by optimisation of 2.5 kW CO 2 laser welding parameters. The D9 alloy, because of its low Cr eq /Ni eq ratio (close to 1), solidified first as primary austenite which makes its welds particularly susceptible to solidification cracking. In this study, the primary mode of solidification in the fusion zone was modulated by controlling the relative degree of fusion of the fuel clad tube and the end plug. A defect free weld with predominantly a primary ferrite mode of solidification was obtained by optimising laser parameters and displacing the focused laser beam towards the end plug side to achieve a greater contribution of end plug material to the fusion zone. The formation of a crater and associated defects at the termination site of lase...
{"title":"Microstructural characterisation of a dissimilar weld of alloy D9 and AISI 316M stainless steel produced using a 2.5 kW CW CO 2 laser","authors":"R. Kaul, P. Ganesh, M. O. Ittoop, A. Nath, Aniruddha Kumar, R. Bhatt, Arun Kumar","doi":"10.1080/0898150021000014083","DOIUrl":"https://doi.org/10.1080/0898150021000014083","url":null,"abstract":"The dissimilar weld, a fuel clad tube (D9 alloy) and an end plug made of AISI 316M forms a part of the fuel pin in the 500 MW Indian Prototype Fast Breeder Reactor (PFBR). The present study aimed at the development of a crack resistant microstructure of the dissimilar weld by optimisation of 2.5 kW CO 2 laser welding parameters. The D9 alloy, because of its low Cr eq /Ni eq ratio (close to 1), solidified first as primary austenite which makes its welds particularly susceptible to solidification cracking. In this study, the primary mode of solidification in the fusion zone was modulated by controlling the relative degree of fusion of the fuel clad tube and the end plug. A defect free weld with predominantly a primary ferrite mode of solidification was obtained by optimising laser parameters and displacing the focused laser beam towards the end plug side to achieve a greater contribution of end plug material to the fusion zone. The formation of a crater and associated defects at the termination site of lase...","PeriodicalId":49918,"journal":{"name":"Lasers in Engineering","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89604058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1080/08981500290022789
J. Grum, D. Zuljan
Efficient control of laser cutting processes is closely related to knowledge of heat effects in the cutting front and its surroundings. Similar to other machining processes using high power densities, in laser cutting processes it is very important to monitor the heating phenomena in the specimen material due to heat input. The processes in the laser cutting front were monitored in three ways, i.e., by a voltage signal of infrared (IR) radiation from the cutting front by measuring surface profiles of laser cuts, and by macrographs of laser cut surfaces. In the paper it is shown that an analysis of macrographs showing surface-profile corrugation of the laser cut at austenitic stainless steel as well as at low-carbon steel can be used to confirm and analyse thermal phenomena in the cutting front. A comparison is given between the power spectra of the voltage signal of the IR radiation and those of the surface-corrugation profile for different steel grades, different specimen thicknesses, and various input e...
{"title":"Frequency analyses of a signal of IR radiation from the cutting front and surface profile height in laser cutting of austenitic stainless steel","authors":"J. Grum, D. Zuljan","doi":"10.1080/08981500290022789","DOIUrl":"https://doi.org/10.1080/08981500290022789","url":null,"abstract":"Efficient control of laser cutting processes is closely related to knowledge of heat effects in the cutting front and its surroundings. Similar to other machining processes using high power densities, in laser cutting processes it is very important to monitor the heating phenomena in the specimen material due to heat input. The processes in the laser cutting front were monitored in three ways, i.e., by a voltage signal of infrared (IR) radiation from the cutting front by measuring surface profiles of laser cuts, and by macrographs of laser cut surfaces. In the paper it is shown that an analysis of macrographs showing surface-profile corrugation of the laser cut at austenitic stainless steel as well as at low-carbon steel can be used to confirm and analyse thermal phenomena in the cutting front. A comparison is given between the power spectra of the voltage signal of the IR radiation and those of the surface-corrugation profile for different steel grades, different specimen thicknesses, and various input e...","PeriodicalId":49918,"journal":{"name":"Lasers in Engineering","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80143992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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