The corrosions resulting from defects in painting layers frequently occur in Al alloys, so the application of corrosion preventing systems is also very important. Optimum conditions in terms of electrochemistry in rel...The corrosions resulting from defects in painting layers frequently occur in Al alloys, so the application of corrosion preventing systems is also very important. Optimum conditions in terms of electrochemistry in relation to solution treatment, quenching and artificial aging treatment were established in order to optimize precipitation strengthening conditions intended to enhance the strength of Al alloys. Slow strain rate tests （SSRT） at various applied potentials were conducted in potential range from -1.8 to 0.5 V. The results show that the maximum tensile strengths, elongations and time-to-fracture are shown to be high values. After precipitation strengthening heat treatment, a tendency appear that time-to-fracture increases as elongation increases. In the potential range from -1.3 V to -0.7 V, the specimens show excellent mechanical properties, and thus this range is considered to be a corrosion prevention range.展开更多
Mg-5Li-3Al-2Zn-xCe（x=0-2.5;mass fraction,%） alloys were prepared by casting,and heat treatments of homogenization at 300 °C and solid solution at 370 °C were carried out.The microstructure and tensile prop...Mg-5Li-3Al-2Zn-xCe（x=0-2.5;mass fraction,%） alloys were prepared by casting,and heat treatments of homogenization at 300 °C and solid solution at 370 °C were carried out.The microstructure and tensile properties of as-cast alloys and their evolutions after solid solution were investigated.The results show that with the increase of Ce content,Al2Ce/Al3Ce precipitates are formed and the alloys mainly consist of α-Mg,Al2Ce,Al3Ce and AlLi phases,and the amount of AlLi and Al-Ce intermetallics decreases after solid solution.The content and morphology of the second phases have important effects on the mechanical properties of the alloys;the alloy with 1.0%Ce content exhibits excellent tensile strength.The tensile strength and elongation of Mg-5Li-3Al-2Zn-0.5Ce alloy is remarkably improved by the solution strengthening effect because of the addition of Ce.展开更多
Mechanical properties of aluminum−silicon−copper alloys are enhanced through precipitation hardening.The response of these alloys to age-hardening is very slow.To overcome this problem,0.2,0.4 and 0.7 wt.%magnesium we...Mechanical properties of aluminum−silicon−copper alloys are enhanced through precipitation hardening.The response of these alloys to age-hardening is very slow.To overcome this problem,0.2,0.4 and 0.7 wt.%magnesium were added to Al−10.5Si−3.4Cu alloy.The new alloys were subjected to two types of precipitation hardening processes different in the solutionizing stage.The results showed that the presence of various amounts of magnesium in the composition of this alloy accelerates the response to ageing treatments,increasing the hardness and strength.Higher mechanical properties can be achieved when the alloys were subjected to a two-stage solution heat treatment.It is found that Al−10.5Si−3.4Cu alloy containing 0.2 wt.%Mg treated through a two-stage solution process,has optimum properties with ultimate tensile strength of 383.9 MPa,yield strength of 289.7 MPa and elongation of 3.97%,and can be used as a substitute for a large number of aluminum castings which need high strength and excellent castability.展开更多
文摘The corrosions resulting from defects in painting layers frequently occur in Al alloys, so the application of corrosion preventing systems is also very important. Optimum conditions in terms of electrochemistry in relation to solution treatment, quenching and artificial aging treatment were established in order to optimize precipitation strengthening conditions intended to enhance the strength of Al alloys. Slow strain rate tests （SSRT） at various applied potentials were conducted in potential range from -1.8 to 0.5 V. The results show that the maximum tensile strengths, elongations and time-to-fracture are shown to be high values. After precipitation strengthening heat treatment, a tendency appear that time-to-fracture increases as elongation increases. In the potential range from -1.3 V to -0.7 V, the specimens show excellent mechanical properties, and thus this range is considered to be a corrosion prevention range.
基金Project (51001034) supported by the National Natural Science Foundation of ChinaProjects (2008AA4CH044, 2009AA1AG065,2010AA4BE031) supported by the Key Project of Science and Technology of Harbin City, China+2 种基金Project (HEUCF201210004) supported by the Fundamental Research Funds for the Central Universities,ChinaProject (20092304120020) supported by the Research Fund for the Doctoral Program of Higher Education,ChinaProject (11553054) supported by the Project of Science and Technology of Heilongjiang Province Education Department,China
文摘Mg-5Li-3Al-2Zn-xCe（x=0-2.5;mass fraction,%） alloys were prepared by casting,and heat treatments of homogenization at 300 °C and solid solution at 370 °C were carried out.The microstructure and tensile properties of as-cast alloys and their evolutions after solid solution were investigated.The results show that with the increase of Ce content,Al2Ce/Al3Ce precipitates are formed and the alloys mainly consist of α-Mg,Al2Ce,Al3Ce and AlLi phases,and the amount of AlLi and Al-Ce intermetallics decreases after solid solution.The content and morphology of the second phases have important effects on the mechanical properties of the alloys;the alloy with 1.0%Ce content exhibits excellent tensile strength.The tensile strength and elongation of Mg-5Li-3Al-2Zn-0.5Ce alloy is remarkably improved by the solution strengthening effect because of the addition of Ce.
文摘Mechanical properties of aluminum−silicon−copper alloys are enhanced through precipitation hardening.The response of these alloys to age-hardening is very slow.To overcome this problem,0.2,0.4 and 0.7 wt.%magnesium were added to Al−10.5Si−3.4Cu alloy.The new alloys were subjected to two types of precipitation hardening processes different in the solutionizing stage.The results showed that the presence of various amounts of magnesium in the composition of this alloy accelerates the response to ageing treatments,increasing the hardness and strength.Higher mechanical properties can be achieved when the alloys were subjected to a two-stage solution heat treatment.It is found that Al−10.5Si−3.4Cu alloy containing 0.2 wt.%Mg treated through a two-stage solution process,has optimum properties with ultimate tensile strength of 383.9 MPa,yield strength of 289.7 MPa and elongation of 3.97%,and can be used as a substitute for a large number of aluminum castings which need high strength and excellent castability.
