Variations in composition,microhardness(in the thermomechanically affected zone)and texture in the tool domain of the dissimilar friction stir weld of AA5083-O and AA6082-T6alloys were investigated.The contents of the...Variations in composition,microhardness(in the thermomechanically affected zone)and texture in the tool domain of the dissimilar friction stir weld of AA5083-O and AA6082-T6alloys were investigated.The contents of the major alloying elements in the weld zones were determined using inductively coupled plasma-atomic emission spectroscopy.It was observed that a slight drop in the content of the alloying elements results from the friction stir welding process with the Mg content being the most affected amongst the major alloying elements in the two alloys.By relating the mass fractions of the major alloying elements in the parent metals of both alloys to those of the stir zone,the relative proportions of the two alloys in the stir zone were estimated with the results showing that at least60%of the materials in the stir zone are from the retreating side of the weld.It was also revealed that the changes in the hardness profile in the thermomechanically affected zone of the retreating side are predominantly influenced by changes in grain size in that domain.Finally,the investigation further revealed that the texture component in the tool shoulder domain is different from the texture component in the tool pin domain.展开更多
Ore grades are currently declining and mines are increasingly required to operate more efficiently in order to save costs and conserve resources. As a result, automated procedures to control and measure process effici...Ore grades are currently declining and mines are increasingly required to operate more efficiently in order to save costs and conserve resources. As a result, automated procedures to control and measure process efficiency have become popular: The demand for sustainable mining and metals processing is globally increasing. Mineral Liberation Analysis is a well established technique to analyse and optimize mining processes and its significance to process mineralogy studies and mineral & metallurgical processing has been widely reported. Dedicated systems consisting of an optimized scanning electron microscopes (SEM) and usually several X-ray detectors are an established solution. With the advent of large area SDDs (Silicon drift detector) and progress in stage automation on conventional SEMs, the speed of X-Ray acquisition is no longer a limiting factor. However, until now, the particle analysis packages on commercially available systems do not lend themselves to Mineral Liberation Analysis without significant modification. INCAMineral is a new solution for mineral liberation analysis which runs on conventional SEMs equipped with large area SDDs.展开更多
Biomaterials are widely used as orthopaedic implants and bone graft substitutes.We aimed to develop a rapid osteogenic assessment method using a murine tibial periosteal ossification model to evaluate the bone forma-t...Biomaterials are widely used as orthopaedic implants and bone graft substitutes.We aimed to develop a rapid osteogenic assessment method using a murine tibial periosteal ossification model to evaluate the bone forma-tion/remodelling potential of a biomaterial within 2-4 weeks.A novel hydroxyapatite/aragonite(HAA)biomaterial was implanted into C57BL/6 mice juxtaskeletally between the tibia and tibialis anterior muscle.Rapid intramembranous bone formation was observed at 14 days,with 4-to 8-fold increases in bone thickness and callus volume in comparison with sham-operated animals(p<0.0001),followed by bone remodelling and a new layer of cortical bone formation by 28 days after implantation.The addition of zoledronate,a clinically-utilised bisphosphonate,to HAA,promoted significantly more new bone formation than HAA alone over 28 days(p<0.01).The osteogenic potential of HAA was further confirmed by implanting into a 3.5 mm diameter femoral cancellous bone defect in rats and a 5 mm diameter femoral cortical bone defect in minipigs.To un-derstand the biodegradation and the cellular activity at the cell/biomaterial interfaces,non-decalcified speci-mens were resin embedded and sections subjected to combined scanning electron microscopy(SEM)/electron backscatter diffraction(EBSD)/energy dispersive X-ray spectrometry(EDS)analysis.We conclude that murine tibial periosteal ossification is a novel method for rapid assessment of the interaction of bioactive materials with osteogenic tissues.This study also highlights that combining calcium carbonate with hydroxyapatite enhances biodegradation and osteogenesis.展开更多
基金the EPSRC for financial support through the LATEST2 Programme Grant
文摘Variations in composition,microhardness(in the thermomechanically affected zone)and texture in the tool domain of the dissimilar friction stir weld of AA5083-O and AA6082-T6alloys were investigated.The contents of the major alloying elements in the weld zones were determined using inductively coupled plasma-atomic emission spectroscopy.It was observed that a slight drop in the content of the alloying elements results from the friction stir welding process with the Mg content being the most affected amongst the major alloying elements in the two alloys.By relating the mass fractions of the major alloying elements in the parent metals of both alloys to those of the stir zone,the relative proportions of the two alloys in the stir zone were estimated with the results showing that at least60%of the materials in the stir zone are from the retreating side of the weld.It was also revealed that the changes in the hardness profile in the thermomechanically affected zone of the retreating side are predominantly influenced by changes in grain size in that domain.Finally,the investigation further revealed that the texture component in the tool shoulder domain is different from the texture component in the tool pin domain.
文摘Ore grades are currently declining and mines are increasingly required to operate more efficiently in order to save costs and conserve resources. As a result, automated procedures to control and measure process efficiency have become popular: The demand for sustainable mining and metals processing is globally increasing. Mineral Liberation Analysis is a well established technique to analyse and optimize mining processes and its significance to process mineralogy studies and mineral & metallurgical processing has been widely reported. Dedicated systems consisting of an optimized scanning electron microscopes (SEM) and usually several X-ray detectors are an established solution. With the advent of large area SDDs (Silicon drift detector) and progress in stage automation on conventional SEMs, the speed of X-Ray acquisition is no longer a limiting factor. However, until now, the particle analysis packages on commercially available systems do not lend themselves to Mineral Liberation Analysis without significant modification. INCAMineral is a new solution for mineral liberation analysis which runs on conventional SEMs equipped with large area SDDs.
基金supported by Royal Society International Exchanges Grant 2021(IES\R1\211128)Qu´ebec-Wales Collaboration Grant 2021 and Wales Innovation Network(WIN)Small Grants Fund(SG6-RIR1058-107).
文摘Biomaterials are widely used as orthopaedic implants and bone graft substitutes.We aimed to develop a rapid osteogenic assessment method using a murine tibial periosteal ossification model to evaluate the bone forma-tion/remodelling potential of a biomaterial within 2-4 weeks.A novel hydroxyapatite/aragonite(HAA)biomaterial was implanted into C57BL/6 mice juxtaskeletally between the tibia and tibialis anterior muscle.Rapid intramembranous bone formation was observed at 14 days,with 4-to 8-fold increases in bone thickness and callus volume in comparison with sham-operated animals(p<0.0001),followed by bone remodelling and a new layer of cortical bone formation by 28 days after implantation.The addition of zoledronate,a clinically-utilised bisphosphonate,to HAA,promoted significantly more new bone formation than HAA alone over 28 days(p<0.01).The osteogenic potential of HAA was further confirmed by implanting into a 3.5 mm diameter femoral cancellous bone defect in rats and a 5 mm diameter femoral cortical bone defect in minipigs.To un-derstand the biodegradation and the cellular activity at the cell/biomaterial interfaces,non-decalcified speci-mens were resin embedded and sections subjected to combined scanning electron microscopy(SEM)/electron backscatter diffraction(EBSD)/energy dispersive X-ray spectrometry(EDS)analysis.We conclude that murine tibial periosteal ossification is a novel method for rapid assessment of the interaction of bioactive materials with osteogenic tissues.This study also highlights that combining calcium carbonate with hydroxyapatite enhances biodegradation and osteogenesis.
