The surface properties of ZM5 Mg-base alloy were modified by laser cladding with Al+Y powder. Laser cladding was carried out with a 5 kW continuous wave CO2 laser by melting the preplaced powder mixture of Al and Y. F...The surface properties of ZM5 Mg-base alloy were modified by laser cladding with Al+Y powder. Laser cladding was carried out with a 5 kW continuous wave CO2 laser by melting the preplaced powder mixture of Al and Y. Following laser cladding, the cladding zone was characterized by a detailed microstructural observation and phase analysis. Moreover, the microhardness and element distribution were evaluated in detail. The surface modified layer consists of Mg17Al12 and Al4MgY phases, while α-Mg and Mg17Al12 in the substrate. The microhardness of the cladding zone was significantly enhanced as high as HV122180 as compared to HV6080 of the substrate region. The maximal hardness about HV224 is in the interface due to the formation of intermetallic Mg17Al12 phase. The microstructure is refined and Mg diffuses into the cladding material which leads to the formation of Mg17Al12.展开更多
In the present paper, the concentration effect of near-infrared quantum cutting of Tm3＋ ion in （Y1-xTmx）3Al5Ol2 powder phosphor is studied by means of experiments and calculations. In addition, the absorption spect...In the present paper, the concentration effect of near-infrared quantum cutting of Tm3＋ ion in （Y1-xTmx）3Al5Ol2 powder phosphor is studied by means of experiments and calculations. In addition, the absorption spectra, visible-to-near- infrared excitation and emission spectra, and fluorescence lifetimes are measured. It is found that （Y1-xTmx）3Al5O12 powder phosphor has a strong four-photon near-infrared quantum cutting luminescence of 1788.0-nm 3F4 →3H6 fluores- cence of Tm3＋ ion, when excited by 357.0-nm light. It is also found that the up-limit of the four-photon near-infrared quantum cutting luminescence efficiency of （Yo.700Tmo.300）3Al5 O12 powder phosphor is approximately 302.19%. To the knowledge of the authors, this is the first time that a near-infrared quantum cutting efficiency up-limit exceeding 300% has been reported. The results of this manuscript are valuable in aiding the probing of the new generation Ge solar cell.展开更多
文摘The surface properties of ZM5 Mg-base alloy were modified by laser cladding with Al+Y powder. Laser cladding was carried out with a 5 kW continuous wave CO2 laser by melting the preplaced powder mixture of Al and Y. Following laser cladding, the cladding zone was characterized by a detailed microstructural observation and phase analysis. Moreover, the microhardness and element distribution were evaluated in detail. The surface modified layer consists of Mg17Al12 and Al4MgY phases, while α-Mg and Mg17Al12 in the substrate. The microhardness of the cladding zone was significantly enhanced as high as HV122180 as compared to HV6080 of the substrate region. The maximal hardness about HV224 is in the interface due to the formation of intermetallic Mg17Al12 phase. The microstructure is refined and Mg diffuses into the cladding material which leads to the formation of Mg17Al12.
基金Project supported by the National Natural Science Foundation of China(Grant No.10674019)the Significant Project of Fundamental Research Funds for the Central Universities of China(Grant No.212-105560GK)
文摘In the present paper, the concentration effect of near-infrared quantum cutting of Tm3＋ ion in （Y1-xTmx）3Al5Ol2 powder phosphor is studied by means of experiments and calculations. In addition, the absorption spectra, visible-to-near- infrared excitation and emission spectra, and fluorescence lifetimes are measured. It is found that （Y1-xTmx）3Al5O12 powder phosphor has a strong four-photon near-infrared quantum cutting luminescence of 1788.0-nm 3F4 →3H6 fluores- cence of Tm3＋ ion, when excited by 357.0-nm light. It is also found that the up-limit of the four-photon near-infrared quantum cutting luminescence efficiency of （Yo.700Tmo.300）3Al5 O12 powder phosphor is approximately 302.19%. To the knowledge of the authors, this is the first time that a near-infrared quantum cutting efficiency up-limit exceeding 300% has been reported. The results of this manuscript are valuable in aiding the probing of the new generation Ge solar cell.
