The morphology changes of both Fe-containing intermetallic compounds and the primary Si phase of Al-20Si-2Fe-2Cu-0.4Mg-1.0Ni-0.5Mn (mass fraction, %) alloy produced by semi-solid rheo-diecasting were studied.The semi-...The morphology changes of both Fe-containing intermetallic compounds and the primary Si phase of Al-20Si-2Fe-2Cu-0.4Mg-1.0Ni-0.5Mn (mass fraction, %) alloy produced by semi-solid rheo-diecasting were studied.The semi-solid slurry of high silicon aluminum alloy was prepared by direct ultrasonic vibration (DUV) which was imposed on the alloy near the liquidus temperature for about 2 min.Then, standard test samples of 6.4 mm in diameter were formed by semi-solid rheo-diecasting.The results show that the DUV treatment suppresses the formation of needle-like β-Al5(Fe,Mn)Si phase, and the Fe-containing intermetallic compounds exist in the form of fine Al4(Fe, Mn)Si2 particles.Additionally, the primary Si grows up as fine and round particles with uniform distribution in α(Al) matrix of this alloy under DUV treatment.The tensile strengths of the samples at the room temperature and 573 K are 230 MPa and 145 MPa, respectively.The coefficient of thermal expansion (CTE) between 25 °C and 300 °C is 16.052 8×10-6 °C-1, and the wear rate is 1.55%.The hardness of this alloy with 2% Fe reaches HB146.3.It is discovered that modified morphology and uniform distribution of the Fe-containing intermetallic compounds and the primary Si phase are the main reasons for reducing the CTE and increasing the wear resistance of this alloy.展开更多
The P ＋ Sr ＋ Ce compound modification technologies of as-cast Al-21Si-1.5Cu-1.5Ni- 2.5Fe- 0.5Mg alloy were investigated by means of orthogonal test. Orthogonal test results show that 3% （CaH2PO4 ＋ 2CASO4）＋ 0.2%...The P ＋ Sr ＋ Ce compound modification technologies of as-cast Al-21Si-1.5Cu-1.5Ni- 2.5Fe- 0.5Mg alloy were investigated by means of orthogonal test. Orthogonal test results show that 3% （CaH2PO4 ＋ 2CASO4）＋ 0.2%Sr ＋ 0.2%Ce is the optimum additive of modification treatment which can fine eutectic and primary silicon also can change the form of rich-iron phase at same time. The needle form of rich-iron phase is Al9FeSi3, which is prored by X-ray diffraction analysis and X-ray energy spectrum analysis. After compound modification treatment, the needle form of rich-iron phase disappeared and the fish bone form of rich-iron and rich-Ce phase that is AlsCeFe emerged. Both at room temperature and at 300℃, the tensile strength of the alloy after the modification treatment with the optimum additive is 30% lager than that of the alloy unmodified. Observed by SEM, the brittle intercrystalline tensile fracture changed into a blended one in which has many dimples.展开更多
A high Fe containing aluminum matrix filler metal for hardfacing aluminum silicon alloys has been developed by using iron,nickel,and silicon as the major strengthening elements,and by measuring mechanical properties...A high Fe containing aluminum matrix filler metal for hardfacing aluminum silicon alloys has been developed by using iron,nickel,and silicon as the major strengthening elements,and by measuring mechanical properties,room temperature and high temperature wear tests,and microstructural analysis.The filler metal,which contains 3.0%-5.0% Fe and 11.0%-13.0% Si,exhibits an excellent weldability.The as cast and as welded microstructures for the filler metal are of uniformly distribution and its dispersed network of hard phase is enriched with Al Si Fe Ni.The filler metal shows high mechanical properties and wear resistance at both room temperature and high temperatures.The deposited metal has a better resistance to impact wear at 220℃ than that of substrate Al Si Mg Cu piston alloy;at room temperature,the deposited metal has an equivalent resistance to slide wear with lubrication as that of a hyper eutectic aluminum silicon alloy with 27% Si and 1% Ni.展开更多
对Al-30%Si合金进行挤压变形并进行半固态等温处理,以求获得细小、圆整的初生硅颗粒.利用光学显微镜、Image Pro Plus金相分析软件等手段测定处理后的初生硅平均直径和形状因子.结果表明,挤压变形能显著细化初生硅颗粒.而半固态等温处理...对Al-30%Si合金进行挤压变形并进行半固态等温处理,以求获得细小、圆整的初生硅颗粒.利用光学显微镜、Image Pro Plus金相分析软件等手段测定处理后的初生硅平均直径和形状因子.结果表明,挤压变形能显著细化初生硅颗粒.而半固态等温处理时,加热温度和保温时间均会对合金组织产生显著影响.在640℃保温10min可获得较佳的合金组织.展开更多
基金Project(2007AA03Z557) supported by the National High-tech Research and Development Program of ChinaProject(50775086) supported by the National Natural Science Foundation of China
文摘The morphology changes of both Fe-containing intermetallic compounds and the primary Si phase of Al-20Si-2Fe-2Cu-0.4Mg-1.0Ni-0.5Mn (mass fraction, %) alloy produced by semi-solid rheo-diecasting were studied.The semi-solid slurry of high silicon aluminum alloy was prepared by direct ultrasonic vibration (DUV) which was imposed on the alloy near the liquidus temperature for about 2 min.Then, standard test samples of 6.4 mm in diameter were formed by semi-solid rheo-diecasting.The results show that the DUV treatment suppresses the formation of needle-like β-Al5(Fe,Mn)Si phase, and the Fe-containing intermetallic compounds exist in the form of fine Al4(Fe, Mn)Si2 particles.Additionally, the primary Si grows up as fine and round particles with uniform distribution in α(Al) matrix of this alloy under DUV treatment.The tensile strengths of the samples at the room temperature and 573 K are 230 MPa and 145 MPa, respectively.The coefficient of thermal expansion (CTE) between 25 °C and 300 °C is 16.052 8×10-6 °C-1, and the wear rate is 1.55%.The hardness of this alloy with 2% Fe reaches HB146.3.It is discovered that modified morphology and uniform distribution of the Fe-containing intermetallic compounds and the primary Si phase are the main reasons for reducing the CTE and increasing the wear resistance of this alloy.
文摘The P ＋ Sr ＋ Ce compound modification technologies of as-cast Al-21Si-1.5Cu-1.5Ni- 2.5Fe- 0.5Mg alloy were investigated by means of orthogonal test. Orthogonal test results show that 3% （CaH2PO4 ＋ 2CASO4）＋ 0.2%Sr ＋ 0.2%Ce is the optimum additive of modification treatment which can fine eutectic and primary silicon also can change the form of rich-iron phase at same time. The needle form of rich-iron phase is Al9FeSi3, which is prored by X-ray diffraction analysis and X-ray energy spectrum analysis. After compound modification treatment, the needle form of rich-iron phase disappeared and the fish bone form of rich-iron and rich-Ce phase that is AlsCeFe emerged. Both at room temperature and at 300℃, the tensile strength of the alloy after the modification treatment with the optimum additive is 30% lager than that of the alloy unmodified. Observed by SEM, the brittle intercrystalline tensile fracture changed into a blended one in which has many dimples.
文摘A high Fe containing aluminum matrix filler metal for hardfacing aluminum silicon alloys has been developed by using iron,nickel,and silicon as the major strengthening elements,and by measuring mechanical properties,room temperature and high temperature wear tests,and microstructural analysis.The filler metal,which contains 3.0%-5.0% Fe and 11.0%-13.0% Si,exhibits an excellent weldability.The as cast and as welded microstructures for the filler metal are of uniformly distribution and its dispersed network of hard phase is enriched with Al Si Fe Ni.The filler metal shows high mechanical properties and wear resistance at both room temperature and high temperatures.The deposited metal has a better resistance to impact wear at 220℃ than that of substrate Al Si Mg Cu piston alloy;at room temperature,the deposited metal has an equivalent resistance to slide wear with lubrication as that of a hyper eutectic aluminum silicon alloy with 27% Si and 1% Ni.
文摘对Al-30%Si合金进行挤压变形并进行半固态等温处理,以求获得细小、圆整的初生硅颗粒.利用光学显微镜、Image Pro Plus金相分析软件等手段测定处理后的初生硅平均直径和形状因子.结果表明,挤压变形能显著细化初生硅颗粒.而半固态等温处理时,加热温度和保温时间均会对合金组织产生显著影响.在640℃保温10min可获得较佳的合金组织.
