In the present study,different structured,Mg-7Gd-4Y-1Zn-0.2Zr(GWZ)and Mg-3Zn-1Al-1Ca-0.5Mn(ZA)alloys based bi-metal composites were fabricated through extrusion.In particular,we reported that the strong and large diff...In the present study,different structured,Mg-7Gd-4Y-1Zn-0.2Zr(GWZ)and Mg-3Zn-1Al-1Ca-0.5Mn(ZA)alloys based bi-metal composites were fabricated through extrusion.In particular,we reported that the strong and large diffusional interfacial thickness comprised of fine grains along with the segregation of the different elements at the interfacial region transferred the load to the base of the composite,and hence acted like a bonder and increased the stability of the interfaces.Most specifically,the rare“composite texture”having c-axes//radial direction(RD)and tilted c-axes//extruded direction(ED)with very low texture intensities was developed in all composites,which is the key requirement for retaining high strength and high ductility.The microstructure of GWZ Mg alloy consists of dense lamellar LPSO_(s),blocky LPSO_(s),rod-shaped LPSO_(s),Mg-enriched rare earth(RE)precipitates,and broken square-shaped RE-enriched precipitates.In contrast,the microstructure of ZA Mg alloy is comprised of MgAl_(2)Ca laves,different-shaped Al_(8)Mn_(5),and nano-sized Mg_(17)Al_(12) precipitates.Particularly,after extrusion,the strongly bonded interfacial region was decorated by Al,Ca,Gd,Y,and Zr elements.The WAW bi-metal composite showed a wavy interfacial morphology compared to the AWA and AW bi-metal composites and the diffusional thickness for all composites was quite large(>20μm).Therefore,based on the above brief discussion,the AWA bi-metal composite(having HAGBs>93%),exhibited exceptionally high performance.The elongation to fracture and strength under compression was significantly higher(EF∼50%,UCS∼17.70%)compared to the GWZ Mg alloy.Likewise,the bendability of the AWA bi-metal composite was much higher(∼103.2%)than the GWZ Mg alloy and higher than other composites.Therefore,the fabrication of bi-metal composites is a practical approach in achieving strength and ductility.展开更多
The Taiwan mountain belt, one of the youngest orogenies in the world, is caused by the collision of the Luzon arc with the Eurasian margin, which leads to post-collisional extension and magmatism in the Northern Taiwa...The Taiwan mountain belt, one of the youngest orogenies in the world, is caused by the collision of the Luzon arc with the Eurasian margin, which leads to post-collisional extension and magmatism in the Northern Taiwan Volcanic Zone(NTVZ). The magma chamber process in this region has not previously been elucidated in detail. In this paper, the textural and compositional features of plagioclase phenocrysts in basalt from the Tatun Volcanic Group(TTVG) were studied to restrict the dynamics of magma system. Results show that the magma melts in TTVG are mainly sourced from the underlying MORB-like mantle wedge but influenced by incorporation of subduction components, causing the elevated Sr/Y and Ba/Y ratios in magma melts. The subduction components are mainly transported in the form of sediment melt. The plagioclase phenocrysts in the TTVG volcanic rocks are generally coarsely core-sieved with a clear rim. The An contents in the rims of plagioclase are much lower than those of cores, and elevated FeO concentrations are detected in the plagioclase rims. We propose there exists a double-layer magma chamber in this region. The core of the plagioclase was crystalized in the deeper quiescent magma chamber(~21 km), which was subsequently partially dissolved during the ascent of magma melt under H_(2)O-undersaturated condition, forming the typical coarsely sieved texture and synneusis. When this crystal-rich melt migrates into the shallower chamber, water saturation is reached and more sodic plagioclase formed as the rim of phenocryst. Due to the considerably higher fO_(2) in the shallow chamber than in the deeper one, and the distribution of Fe between plagioclase and melt positively correlates with fO_(2), the FeO content in the plagioclase rim elevates in conjunction with increasing fO_(2).展开更多
基金fully supported by the National Natural Science Foundation of China RFIS-1(52250410344 and 52250410343)the Deanship of Research and Graduate Studies at King Khalid University for funding this work through Large Research Project under grant number RGP2/277/45.
文摘In the present study,different structured,Mg-7Gd-4Y-1Zn-0.2Zr(GWZ)and Mg-3Zn-1Al-1Ca-0.5Mn(ZA)alloys based bi-metal composites were fabricated through extrusion.In particular,we reported that the strong and large diffusional interfacial thickness comprised of fine grains along with the segregation of the different elements at the interfacial region transferred the load to the base of the composite,and hence acted like a bonder and increased the stability of the interfaces.Most specifically,the rare“composite texture”having c-axes//radial direction(RD)and tilted c-axes//extruded direction(ED)with very low texture intensities was developed in all composites,which is the key requirement for retaining high strength and high ductility.The microstructure of GWZ Mg alloy consists of dense lamellar LPSO_(s),blocky LPSO_(s),rod-shaped LPSO_(s),Mg-enriched rare earth(RE)precipitates,and broken square-shaped RE-enriched precipitates.In contrast,the microstructure of ZA Mg alloy is comprised of MgAl_(2)Ca laves,different-shaped Al_(8)Mn_(5),and nano-sized Mg_(17)Al_(12) precipitates.Particularly,after extrusion,the strongly bonded interfacial region was decorated by Al,Ca,Gd,Y,and Zr elements.The WAW bi-metal composite showed a wavy interfacial morphology compared to the AWA and AW bi-metal composites and the diffusional thickness for all composites was quite large(>20μm).Therefore,based on the above brief discussion,the AWA bi-metal composite(having HAGBs>93%),exhibited exceptionally high performance.The elongation to fracture and strength under compression was significantly higher(EF∼50%,UCS∼17.70%)compared to the GWZ Mg alloy.Likewise,the bendability of the AWA bi-metal composite was much higher(∼103.2%)than the GWZ Mg alloy and higher than other composites.Therefore,the fabrication of bi-metal composites is a practical approach in achieving strength and ductility.
基金funded by the Shandong Provincial Natural Science Foundation, China (No. ZR2019BD010)the National Natural Science Foundation of China (No. 42276085)+2 种基金Open Fund of the Key Laboratory of Marine Geology and Environment, Chinese Academy of Sciences (No. MGE2021KG01)Pilot National Laboratory for Marine Science and Technology (Qingdao) (No. JCZX202014)the Key Laboratory Submarine Geoscience and Prospecting Techniques, Ministry of Education, Ocean university of China。
文摘The Taiwan mountain belt, one of the youngest orogenies in the world, is caused by the collision of the Luzon arc with the Eurasian margin, which leads to post-collisional extension and magmatism in the Northern Taiwan Volcanic Zone(NTVZ). The magma chamber process in this region has not previously been elucidated in detail. In this paper, the textural and compositional features of plagioclase phenocrysts in basalt from the Tatun Volcanic Group(TTVG) were studied to restrict the dynamics of magma system. Results show that the magma melts in TTVG are mainly sourced from the underlying MORB-like mantle wedge but influenced by incorporation of subduction components, causing the elevated Sr/Y and Ba/Y ratios in magma melts. The subduction components are mainly transported in the form of sediment melt. The plagioclase phenocrysts in the TTVG volcanic rocks are generally coarsely core-sieved with a clear rim. The An contents in the rims of plagioclase are much lower than those of cores, and elevated FeO concentrations are detected in the plagioclase rims. We propose there exists a double-layer magma chamber in this region. The core of the plagioclase was crystalized in the deeper quiescent magma chamber(~21 km), which was subsequently partially dissolved during the ascent of magma melt under H_(2)O-undersaturated condition, forming the typical coarsely sieved texture and synneusis. When this crystal-rich melt migrates into the shallower chamber, water saturation is reached and more sodic plagioclase formed as the rim of phenocryst. Due to the considerably higher fO_(2) in the shallow chamber than in the deeper one, and the distribution of Fe between plagioclase and melt positively correlates with fO_(2), the FeO content in the plagioclase rim elevates in conjunction with increasing fO_(2).
