金属材料挤出(metal material extrusion, MME)技术因其生产成本低,材料利率高,设计自由度高,环境友好等特点,在工业设计、医疗器械等领域有着巨大的发展潜力和优势。但是由于逐层累加的制造方式,导致MME产品的机械性能逊色于传统减材...金属材料挤出(metal material extrusion, MME)技术因其生产成本低,材料利率高,设计自由度高,环境友好等特点,在工业设计、医疗器械等领域有着巨大的发展潜力和优势。但是由于逐层累加的制造方式,导致MME产品的机械性能逊色于传统减材方式加工的金属产品。为了提高MME产品的机械性能,提出振动辅助加工的方法,即利用压电陶瓷的逆压电效应将振动引入生坯成型过程,并分别制备了振动辅助与否的拉伸和弯曲生坯试件,再经脱脂-烧结处理形成致密化的纯金属试件;随后分别对生坯和烧结试件进行了静力学试验,并对比分析了振动辅助成型与否的试件的抗拉强度、抗弯强度及应变等参数。研究结果表明,振动辅助加工可以显著提高MME生坯和烧结试件的抗拉和抗弯强度,并有效降低其拉伸和弯曲的正交各向异性特征。展开更多
The Late Cretaceous Mamba granodiorite belongs to a part of the Mesozoic Gangdese continental magmatic belt. No quantitative mineralogical study has been made hitherto, and hence the depth at which it formed is poorly...The Late Cretaceous Mamba granodiorite belongs to a part of the Mesozoic Gangdese continental magmatic belt. No quantitative mineralogical study has been made hitherto, and hence the depth at which it formed is poorly constrained. Here we present mineralogical data for the Mamba pluton, including host rocks and their mafic microgranular enclaves（MMEs）, to provide insights into their overall crystallization conditions and information about magma mixing. All amphiboles in the Mamba pluton are calcic, with ~B（Ca＋Na）〉1.5, and Si=6.81-7.42 apfu for the host rocks and Si=6.77-7.35 apfu for the MMEs. The paramount cation substitutions in amphibole include edenite type and tschermakite type. Biotites both in the host rocks and the MMEs collectively have high Mg O（13.19 wt.%-13.03 wt.%） contents, but define a narrow range of Al apfu（atoms per formula unit） variations（2.44-2.57）. The oxygen fugacity estimates are based on the biotite compositions cluster around the NNO buffer. The calculated pressure ranges from 1.2 to 2.1 kbar according to the aluminum-in-hornblende barometer. The computed pressure varies from 0.9 to 1.3 kbar based on the aluminum-in-biotite barometer which corresponds to an average depth of ca. 3.9 km. Besides, the estimates of crystallization pressures vary from 0.8 to 1.4 kbar based on the amphibole barometer proposed by Ridolfi et al.（2010）, which can be equivalent to the depths ranging from 3.1 to 5.2 km. The MMEs have plagioclase oscillatory zonings and quartz aggregates, probably indicating the presence of magma mixing. Besides, core-to-rim element variations（Rb, Sr, Ba, and P） for the K-feldspar megacrysts serve as robust evidence to support magma mixing and crystal fractionation. This indicates the significance of the magma mixing that contributes to the formation of K-feldspar megacryst zonings in the Mamba pluton.展开更多
The Western Qinling Orogen(WQO) is characterized by voluminous distribution of Indosinian granitoids,the formation of which provides an important window to unravel the geochemical and geodynamic evolution and associat...The Western Qinling Orogen(WQO) is characterized by voluminous distribution of Indosinian granitoids,the formation of which provides an important window to unravel the geochemical and geodynamic evolution and associated metallogeny.Here we investigate a group of intrusions termed "Five Golden Flowers" based on petrological,geochemical,zircon U-Pb geochronological and Lu-Hf isotopic studies on the granitoids and their mafic microgranular enclaves(MMEs).Our results show that these intrusions are genetically divided into two types,namely,magma-mixing and highly fractionated.The Jiaochangba,Lujing,Zhongchuan,and Luchuba granitoids are biotite monzogranites(220±0.8 Ma to 217±2.6 Ma) with abundant coeval MMEs(220±.1 Ma to 217±2.7 Ma).The rocks contain moderate to high SiO2,high MgO,Rb,Sr,Ba,and Th contents,but low TiO2,P2 O5,and Sc values,A/CNK of <1.1,and a range of εHf(t) values of-11.7 to +2.23 with corresponding TDM2values of 1967-1228 Ma.The MMEs possess K-feldspar megacrysts,abundant acicular apatites,and show lopsided textures.They have lower SiO2,Al2 O3,and Th contents,but higher MgO,TiO2,and Sc,with εHf(t) values of-18.0 to +3.18 and TDM1 of 849-720 Ma.The data indicate that the MMEs were derived from a magma sourced from the enriched lithospheric mantle.We suggest that these host granitoids were produced by partial melting of latePaleoproterozoic to early-Mesoproterozoic lower crust with the involvement of Neoproterozoic SCLM-derived mafic magmas.The Baijiazhuang pluton is dominantly composed of leucogranite(muscovite granite and twomica monzogranite,216±1.5 Ma) without MMEs.The rocks are peraluminous with high A/CNK(1.06-1.27).Compared with the other four granitoids,the Baijiazhuang leucogranite shows higher SiO2 content,markedly lower concentrations of TiO2,MgO,Al2 O3,CaO,and Fe2 O3T,and lower LREE/HREE and(La/Yb)N values.These leucogranites are also rich in Rb,Th,and U,and display marked depletions in Ba,Sr,Ti,and Eu,indicating that they experienced significant fractionation.Zircon εHf(t) values(-10.2 to-3.27) and TDM2(1868-1424 Ma),as well as the Nb/Ta and K2 O/Na2 O values are similar to the other four granitoids,indicating that they are likely to have been derived from a similar source;with sediments playing only a minor role in the magma generation.The low contents of Yb and Y suggest that their partial melting was controlled by garnets and micrographic texture of K-feldspar reflects high-temperature melting through undercooling.Based on the above features,we infer that the Baijiazhuang leucogranite likely represents the product of high degree fractionation of the I-type biotite monzogranite magma which generated the other four granitoids at relatively high temperatures,within magma chambers at mid-crust depths.We propose that the granitoid suite was formed in the transitional setting from synto post-collision during the collisional orogeny between the SCB and NCB,following break-off of the subducted South China Block lithosphere during 220-216 Ma.展开更多
文摘金属材料挤出(metal material extrusion, MME)技术因其生产成本低,材料利率高,设计自由度高,环境友好等特点,在工业设计、医疗器械等领域有着巨大的发展潜力和优势。但是由于逐层累加的制造方式,导致MME产品的机械性能逊色于传统减材方式加工的金属产品。为了提高MME产品的机械性能,提出振动辅助加工的方法,即利用压电陶瓷的逆压电效应将振动引入生坯成型过程,并分别制备了振动辅助与否的拉伸和弯曲生坯试件,再经脱脂-烧结处理形成致密化的纯金属试件;随后分别对生坯和烧结试件进行了静力学试验,并对比分析了振动辅助成型与否的试件的抗拉强度、抗弯强度及应变等参数。研究结果表明,振动辅助加工可以显著提高MME生坯和烧结试件的抗拉和抗弯强度,并有效降低其拉伸和弯曲的正交各向异性特征。
基金funded by the National Natural Science Foundation of China (Nos. 41403028, 40830317)the China Postdoctoral Science Foundation (No. 2015T80113)+1 种基金China University of Geosciences (No. GMPR201509)the Fundamental Research Funds for the Central Universities of China (No. 2652015018)
文摘The Late Cretaceous Mamba granodiorite belongs to a part of the Mesozoic Gangdese continental magmatic belt. No quantitative mineralogical study has been made hitherto, and hence the depth at which it formed is poorly constrained. Here we present mineralogical data for the Mamba pluton, including host rocks and their mafic microgranular enclaves（MMEs）, to provide insights into their overall crystallization conditions and information about magma mixing. All amphiboles in the Mamba pluton are calcic, with ~B（Ca＋Na）〉1.5, and Si=6.81-7.42 apfu for the host rocks and Si=6.77-7.35 apfu for the MMEs. The paramount cation substitutions in amphibole include edenite type and tschermakite type. Biotites both in the host rocks and the MMEs collectively have high Mg O（13.19 wt.%-13.03 wt.%） contents, but define a narrow range of Al apfu（atoms per formula unit） variations（2.44-2.57）. The oxygen fugacity estimates are based on the biotite compositions cluster around the NNO buffer. The calculated pressure ranges from 1.2 to 2.1 kbar according to the aluminum-in-hornblende barometer. The computed pressure varies from 0.9 to 1.3 kbar based on the aluminum-in-biotite barometer which corresponds to an average depth of ca. 3.9 km. Besides, the estimates of crystallization pressures vary from 0.8 to 1.4 kbar based on the amphibole barometer proposed by Ridolfi et al.（2010）, which can be equivalent to the depths ranging from 3.1 to 5.2 km. The MMEs have plagioclase oscillatory zonings and quartz aggregates, probably indicating the presence of magma mixing. Besides, core-to-rim element variations（Rb, Sr, Ba, and P） for the K-feldspar megacrysts serve as robust evidence to support magma mixing and crystal fractionation. This indicates the significance of the magma mixing that contributes to the formation of K-feldspar megacryst zonings in the Mamba pluton.
基金This study was jointly supported by National Natural Science Foundation of China (Grant Nos.41730426,41421002,41272092 and 41803039)MOST Special Fund from the State Key Laboratory of Continental Dynamics,Northwest University,China
文摘The Western Qinling Orogen(WQO) is characterized by voluminous distribution of Indosinian granitoids,the formation of which provides an important window to unravel the geochemical and geodynamic evolution and associated metallogeny.Here we investigate a group of intrusions termed "Five Golden Flowers" based on petrological,geochemical,zircon U-Pb geochronological and Lu-Hf isotopic studies on the granitoids and their mafic microgranular enclaves(MMEs).Our results show that these intrusions are genetically divided into two types,namely,magma-mixing and highly fractionated.The Jiaochangba,Lujing,Zhongchuan,and Luchuba granitoids are biotite monzogranites(220±0.8 Ma to 217±2.6 Ma) with abundant coeval MMEs(220±.1 Ma to 217±2.7 Ma).The rocks contain moderate to high SiO2,high MgO,Rb,Sr,Ba,and Th contents,but low TiO2,P2 O5,and Sc values,A/CNK of <1.1,and a range of εHf(t) values of-11.7 to +2.23 with corresponding TDM2values of 1967-1228 Ma.The MMEs possess K-feldspar megacrysts,abundant acicular apatites,and show lopsided textures.They have lower SiO2,Al2 O3,and Th contents,but higher MgO,TiO2,and Sc,with εHf(t) values of-18.0 to +3.18 and TDM1 of 849-720 Ma.The data indicate that the MMEs were derived from a magma sourced from the enriched lithospheric mantle.We suggest that these host granitoids were produced by partial melting of latePaleoproterozoic to early-Mesoproterozoic lower crust with the involvement of Neoproterozoic SCLM-derived mafic magmas.The Baijiazhuang pluton is dominantly composed of leucogranite(muscovite granite and twomica monzogranite,216±1.5 Ma) without MMEs.The rocks are peraluminous with high A/CNK(1.06-1.27).Compared with the other four granitoids,the Baijiazhuang leucogranite shows higher SiO2 content,markedly lower concentrations of TiO2,MgO,Al2 O3,CaO,and Fe2 O3T,and lower LREE/HREE and(La/Yb)N values.These leucogranites are also rich in Rb,Th,and U,and display marked depletions in Ba,Sr,Ti,and Eu,indicating that they experienced significant fractionation.Zircon εHf(t) values(-10.2 to-3.27) and TDM2(1868-1424 Ma),as well as the Nb/Ta and K2 O/Na2 O values are similar to the other four granitoids,indicating that they are likely to have been derived from a similar source;with sediments playing only a minor role in the magma generation.The low contents of Yb and Y suggest that their partial melting was controlled by garnets and micrographic texture of K-feldspar reflects high-temperature melting through undercooling.Based on the above features,we infer that the Baijiazhuang leucogranite likely represents the product of high degree fractionation of the I-type biotite monzogranite magma which generated the other four granitoids at relatively high temperatures,within magma chambers at mid-crust depths.We propose that the granitoid suite was formed in the transitional setting from synto post-collision during the collisional orogeny between the SCB and NCB,following break-off of the subducted South China Block lithosphere during 220-216 Ma.
