In this study,the effect of inclination angles relative to the building direction in the additively manufactured eutectic Al-5Mg-2Si alloy was investigated through the laser powder bed fusion(LPBF).The microstructures...In this study,the effect of inclination angles relative to the building direction in the additively manufactured eutectic Al-5Mg-2Si alloy was investigated through the laser powder bed fusion(LPBF).The microstructures and mechanical properties of the Al-5Mg-2Si alloy manufactured with different inclination angles(0°,30°,45°,60°and 90°)were reported and discussed.It is found that the“semicircular”melt pool(MP)in the load bearing face of 0°sample was eventually transformed into“stripe-like”MP in the 90°sample,accompanied by an increased fraction of melt pool boundaries(MPBs).Moreover,the microstructural analysis revealed that the columnar-to-equiaxed transition(CET)of theα-Al grains and eutectic Mg2Si was completed in the 90°sample,which were significantly refined with the average size of 10.6μm and 0.44μm,respectively.It is also found that the 90°sample exhibited good combination of strength and elongation(i.e.yield strength of 393 MPa,ultimate tensile strength of 483 MPa and elongation of 8.1%).The anisotropic mechanical properties were highly associated with the refined microstructures,thermal stress,and density of MPBs.Additionally,the CET driven by inclination angles was attributed to the variation of thermal conditions inside the local MPs.展开更多
[Objective] The aim was to obtain the best planting density and the best fertilizer of purple flesh sweetpotato so as to provide theoretical basis for breeding of high yield and quality of purple flesh sweetpotato in ...[Objective] The aim was to obtain the best planting density and the best fertilizer of purple flesh sweetpotato so as to provide theoretical basis for breeding of high yield and quality of purple flesh sweetpotato in Chongqing.[Method] The effects of fertilization,planting density and variety on yield of purple flesh sweetpotato were studied by orthogonal test of L9（34）.Residential treatment was：fertilization（A）,300 kg/hm2（A1）,600 kg/hm2（A2）,900 kg/hm2（A2）;density（B）,45 000 Plants/hm2（B1）,60 000 Plants/hm2（B2）,75 000 Plants/hm2（B3）;species（C）,Wanzi 56（C1）,Yuzi 43（C2）,Yuzi 263（C3）.[Result] The yield of Wanzi 56 was the highest among three purple flesh cultivars on conditions that planting density was 75 000 plants/hm2,and fertilization was 300 kg/hm2.The influence of planting density for yield of purple flesh sweetpotato was higher than that of fertilization.The orders of different levels of various factors on the test results was A factor column,K1〉K2〉K3;B factor column,K3〉K1〉K2;C factors column,K1〉K3〉K2.[Conclusion] The yield of Wanzi 56 was highest,follow by the yizi263 and yuzi43.The optimum planting density was 75 000 plants/hm2,and the most reasonable amount of fertilizer was 300 kg/hm2.展开更多
基金Project(52071343)supported by the National Natural Science Foundation of China。
文摘In this study,the effect of inclination angles relative to the building direction in the additively manufactured eutectic Al-5Mg-2Si alloy was investigated through the laser powder bed fusion(LPBF).The microstructures and mechanical properties of the Al-5Mg-2Si alloy manufactured with different inclination angles(0°,30°,45°,60°and 90°)were reported and discussed.It is found that the“semicircular”melt pool(MP)in the load bearing face of 0°sample was eventually transformed into“stripe-like”MP in the 90°sample,accompanied by an increased fraction of melt pool boundaries(MPBs).Moreover,the microstructural analysis revealed that the columnar-to-equiaxed transition(CET)of theα-Al grains and eutectic Mg2Si was completed in the 90°sample,which were significantly refined with the average size of 10.6μm and 0.44μm,respectively.It is also found that the 90°sample exhibited good combination of strength and elongation(i.e.yield strength of 393 MPa,ultimate tensile strength of 483 MPa and elongation of 8.1%).The anisotropic mechanical properties were highly associated with the refined microstructures,thermal stress,and density of MPBs.Additionally,the CET driven by inclination angles was attributed to the variation of thermal conditions inside the local MPs.
基金Supported by Construction Foundation of Modern Agricultural Industry and Technology System(nycytx-16-B-4)Chongqing Special Funds for Basic Research and Operating Expenses~~
文摘[Objective] The aim was to obtain the best planting density and the best fertilizer of purple flesh sweetpotato so as to provide theoretical basis for breeding of high yield and quality of purple flesh sweetpotato in Chongqing.[Method] The effects of fertilization,planting density and variety on yield of purple flesh sweetpotato were studied by orthogonal test of L9（34）.Residential treatment was：fertilization（A）,300 kg/hm2（A1）,600 kg/hm2（A2）,900 kg/hm2（A2）;density（B）,45 000 Plants/hm2（B1）,60 000 Plants/hm2（B2）,75 000 Plants/hm2（B3）;species（C）,Wanzi 56（C1）,Yuzi 43（C2）,Yuzi 263（C3）.[Result] The yield of Wanzi 56 was the highest among three purple flesh cultivars on conditions that planting density was 75 000 plants/hm2,and fertilization was 300 kg/hm2.The influence of planting density for yield of purple flesh sweetpotato was higher than that of fertilization.The orders of different levels of various factors on the test results was A factor column,K1〉K2〉K3;B factor column,K3〉K1〉K2;C factors column,K1〉K3〉K2.[Conclusion] The yield of Wanzi 56 was highest,follow by the yizi263 and yuzi43.The optimum planting density was 75 000 plants/hm2,and the most reasonable amount of fertilizer was 300 kg/hm2.
