In order to improve the comprehensive properties of the Cu-11.9Al-2.5Mn shape memory alloy(SMA),multilayer graphene(MLG)carried by Cu_(51)Zr_(14)inoculant particles was incorporated and dispersed into this alloy throu...In order to improve the comprehensive properties of the Cu-11.9Al-2.5Mn shape memory alloy(SMA),multilayer graphene(MLG)carried by Cu_(51)Zr_(14)inoculant particles was incorporated and dispersed into this alloy through preparing the preform of the cold-pressed MLG-Cu_(51)Zr_(14)composite powders.In the resultant novel MLG/Cu-Al-Mn composites,MLG in fragmented or flocculent form has a good bonding with the Cu-Al-Mn matrix.MLG can prevent the coarsening of grains of the Cu-Al-Mn SMA and cause thermal mismatch dislocations near the MLG/Cu-Al-Mn interfaces.The damping and mechanical properties of the MLG/Cu-Al-Mn composites are significantly improved.When the content of MLG reaches 0.2 wt.%,the highest room temperature damping of 0.0558,tensile strength of 801.5 MPa,elongation of 10.8%,and hardness of HV 308 can be obtained.On the basis of in-depth observation of microstructures,combined with the theory of internal friction and strengthening and toughening theories of metals,the relevant mechanisms are discussed.展开更多
利用共沉淀法制备了四组分的Cu Zn Al Mn和Cu Zn Al Ce催化剂以及三组分的Cu Zn Al催化剂。利用组成H2/CO/CO2/N2=66/27/3/4(体积比)的富CO原料气对催化剂进行了活性评价,并研究了温度、压力和空速等反应条件对催化剂活性的影响。结果...利用共沉淀法制备了四组分的Cu Zn Al Mn和Cu Zn Al Ce催化剂以及三组分的Cu Zn Al催化剂。利用组成H2/CO/CO2/N2=66/27/3/4(体积比)的富CO原料气对催化剂进行了活性评价,并研究了温度、压力和空速等反应条件对催化剂活性的影响。结果发现添加适量的锰助剂能显著提高催化剂的活性和热稳定性。利用SEM和XRD方法进行了催化剂的结构和形貌表征,同样表明锰助剂可以起到阻止CuO晶粒长大和促进CuO分散作用。利用富CO2的生物质原料气体积比为H2/CO/CO2/N2=50/25/20/5对Cu Zn Al Mn催化剂进行的评价表明:Cu Zn Al Mn催化剂上CO/CO2加氢合成甲醇的甲醇产率和选择性均有下降,在试验范围内,甲醇产率下降11%～25%,选择性为93%～95%。展开更多
通过拉伸和埃里克森实验以及扫描电镜/能谱、透射电镜和金相分析,研究Mn的质量分数对Al Mg Si Cu铝合金汽车板显微组织、力学性能和成形性的影响·研究表明,随Mn质量分数增加,Al Mg Si Cu汽车板铝合金不可溶结晶相及弥散相粒子数量...通过拉伸和埃里克森实验以及扫描电镜/能谱、透射电镜和金相分析,研究Mn的质量分数对Al Mg Si Cu铝合金汽车板显微组织、力学性能和成形性的影响·研究表明,随Mn质量分数增加,Al Mg Si Cu汽车板铝合金不可溶结晶相及弥散相粒子数量均增加,不可溶结晶相使合金组织纤维化对板材冲压成形性不利,弥散相粒子阻碍再结晶晶粒长大;提高Mn的质量分数,Al Mg Si Cu汽车板铝合金的强度增加,但延伸率和冲压成形性降低·展开更多
The microstructure evolution of Al-Cu-Li-Mn-Zr-Ti alloy during homogenization was investigated by optical microscopy （OM）, scanning electron microscopy （SEM）, energy dispersive X-ray spectrometry （EDX）, and diff...The microstructure evolution of Al-Cu-Li-Mn-Zr-Ti alloy during homogenization was investigated by optical microscopy （OM）, scanning electron microscopy （SEM）, energy dispersive X-ray spectrometry （EDX）, and differential scanning calorimeter （DSC） methods. The results show that severe dendritic segregation exists in the experimental alloy ingot. Numerous eutectic phases can be observed in the grain boundary, and the distribution of the main elements along the interdendritic region varies periodically. The main secondary phase is Al2Cu. The overburnt temperature of the alloy is 520 °C. The second phases are gradually dissolved into the matrix, and the grain boundaries become spare and thin during homogenization with increasing temperature or prolonging holding time. Homogenization can be described by a constitutive equation in exponential function. The suitable homogenization treatment for the alloy is （510 °C, 18 h）, which agrees well with the results of homogenization kinetic analysis.展开更多
基金supported by the Natural Science Foundation of Hebei Province,China(No.E2021202017)the National Natural Science Foundation of China(No.52061038)+3 种基金the Foundation Strengthening Program,China(No.2019-JCJQ-ZD-142-00)the Hebei Province Graduate Innovation Funding Project,China(No.CXZZBS2022032)the Jiangsu Provincial Policy Guidance Program(Special Project for the Introduction of Foreign Talents)Talent Introduction Program,China(No.BX2021024)the Science Plan Foundation of Tianjin Municipal Education Commission,China(No.2021KJ026)。
文摘In order to improve the comprehensive properties of the Cu-11.9Al-2.5Mn shape memory alloy(SMA),multilayer graphene(MLG)carried by Cu_(51)Zr_(14)inoculant particles was incorporated and dispersed into this alloy through preparing the preform of the cold-pressed MLG-Cu_(51)Zr_(14)composite powders.In the resultant novel MLG/Cu-Al-Mn composites,MLG in fragmented or flocculent form has a good bonding with the Cu-Al-Mn matrix.MLG can prevent the coarsening of grains of the Cu-Al-Mn SMA and cause thermal mismatch dislocations near the MLG/Cu-Al-Mn interfaces.The damping and mechanical properties of the MLG/Cu-Al-Mn composites are significantly improved.When the content of MLG reaches 0.2 wt.%,the highest room temperature damping of 0.0558,tensile strength of 801.5 MPa,elongation of 10.8%,and hardness of HV 308 can be obtained.On the basis of in-depth observation of microstructures,combined with the theory of internal friction and strengthening and toughening theories of metals,the relevant mechanisms are discussed.
文摘利用共沉淀法制备了四组分的Cu Zn Al Mn和Cu Zn Al Ce催化剂以及三组分的Cu Zn Al催化剂。利用组成H2/CO/CO2/N2=66/27/3/4(体积比)的富CO原料气对催化剂进行了活性评价,并研究了温度、压力和空速等反应条件对催化剂活性的影响。结果发现添加适量的锰助剂能显著提高催化剂的活性和热稳定性。利用SEM和XRD方法进行了催化剂的结构和形貌表征,同样表明锰助剂可以起到阻止CuO晶粒长大和促进CuO分散作用。利用富CO2的生物质原料气体积比为H2/CO/CO2/N2=50/25/20/5对Cu Zn Al Mn催化剂进行的评价表明:Cu Zn Al Mn催化剂上CO/CO2加氢合成甲醇的甲醇产率和选择性均有下降,在试验范围内,甲醇产率下降11%～25%,选择性为93%～95%。
文摘通过拉伸和埃里克森实验以及扫描电镜/能谱、透射电镜和金相分析,研究Mn的质量分数对Al Mg Si Cu铝合金汽车板显微组织、力学性能和成形性的影响·研究表明,随Mn质量分数增加,Al Mg Si Cu汽车板铝合金不可溶结晶相及弥散相粒子数量均增加,不可溶结晶相使合金组织纤维化对板材冲压成形性不利,弥散相粒子阻碍再结晶晶粒长大;提高Mn的质量分数,Al Mg Si Cu汽车板铝合金的强度增加,但延伸率和冲压成形性降低·
文摘The microstructure evolution of Al-Cu-Li-Mn-Zr-Ti alloy during homogenization was investigated by optical microscopy （OM）, scanning electron microscopy （SEM）, energy dispersive X-ray spectrometry （EDX）, and differential scanning calorimeter （DSC） methods. The results show that severe dendritic segregation exists in the experimental alloy ingot. Numerous eutectic phases can be observed in the grain boundary, and the distribution of the main elements along the interdendritic region varies periodically. The main secondary phase is Al2Cu. The overburnt temperature of the alloy is 520 °C. The second phases are gradually dissolved into the matrix, and the grain boundaries become spare and thin during homogenization with increasing temperature or prolonging holding time. Homogenization can be described by a constitutive equation in exponential function. The suitable homogenization treatment for the alloy is （510 °C, 18 h）, which agrees well with the results of homogenization kinetic analysis.
