The main methods of the second phase quantitative analysis in current material science researches are manual recognition and extracting by using software such as Image Tool and Nano Measurer. The weaknesses such as hi...The main methods of the second phase quantitative analysis in current material science researches are manual recognition and extracting by using software such as Image Tool and Nano Measurer. The weaknesses such as high labor intensity and low accuracy statistic results exist in these methods. In order to overcome the shortcomings of the current methods, the Ω phase in A1-Cu-Mg-Ag alloy is taken as the research object and an algorithm based on the digital image processing and pattern recognition is proposed and implemented to do the A1 alloy TEM （transmission electron microscope） digital images process and recognize and extract the information of the second phase in the result image automatically. The top-hat transformation of the mathematical morphology, as well as several imaging processing technologies has been used in the proposed algorithm. Thereinto, top-hat transformation is used for elimination of asymmetric illumination and doing Multi-layer filtering to segment Ω phase in the TEM image. The testing results are satisfied, which indicate that the Ω phase with unclear boundary or small size can be recognized by using this method. The omission of these two kinds of Ω phase can be avoided or significantly reduced. More Ω phases would be recognized （growing rate minimum to 2% and maximum to 400% in samples）, accuracy of recognition and statistics results would be greatly improved by using this method. And the manual error can be eliminated. The procedure recognizing and making quantitative analysis of information in this method is automatically completed by the software. It can process one image, including recognition and quantitative analysis in 30 min, but the manual method such as using Image Tool or Nano Measurer need 2 h or more. The labor intensity is effectively reduced and the working efficiency is greatly improved.展开更多
A finite domain time difference （FDTD） and second-derivative combined method is proposed for the evaluation of phase center in the Fresnel region of complex structure millimeter antennas. This method adopts FDTD＇s ...A finite domain time difference （FDTD） and second-derivative combined method is proposed for the evaluation of phase center in the Fresnel region of complex structure millimeter antennas. This method adopts FDTD＇s near to far field transformation to obtain the fields in Fresnel region and then applies the second-derivative method to calculate the phase center. The adoption of FDTD efficiently overcomes the difficulties arising from the existing calculation methods＇ requirements for the radiation analytical formula of some complex antennas, which makes the existing second-derivative method more applicable in engineering. Also, FDTD increases the precision owing to the superposition field calculation from its extrapolation. The correctness of this proposed method is certified with typical examples and the phase center in the Fresnel region of a microwave radiometry calibration corrugate horn antenna is evaluated with the key features.展开更多
通过SEM、EDS和XRD,研究了稀土La添加量(0.1wt%、0.2wt%、0.4wt%、0.8wt%)对6082铝合金铸态组织和力学性能的影响。结果表明:稀土La可以明显细化合金晶粒、有效调控第二相并提高合金的力学性能。随着合金中稀土La含量的增加,合金晶粒尺...通过SEM、EDS和XRD,研究了稀土La添加量(0.1wt%、0.2wt%、0.4wt%、0.8wt%)对6082铝合金铸态组织和力学性能的影响。结果表明:稀土La可以明显细化合金晶粒、有效调控第二相并提高合金的力学性能。随着合金中稀土La含量的增加,合金晶粒尺寸先减小后增加,当稀土La含量为0.2wt%时合金的晶粒细化效果最好,此时合金的抗拉强度、屈服强度和伸长率均达到最高,分别为181 MPa、167 MPa和5.43%,明显优于未添加稀土La的合金抗拉强度、屈服强度和伸长率(128 MPa、87 MPa和4.68%)。稀土La的添加能将细长条状的β-Al Fe Si相调控成π状α-Al Si Fe相,大大降低了应力集中,从而有效提高合金的力学性能。展开更多
7000系铝合金因具备低密度、高强和高韧等优点而备受关注,工业中可通过多道次热变形来提升合金的综合性能,要获得接近理想状态下的铝合金性能,必须掌握多道次热变形工艺参数对组织演变造成的影响。本实验采用TA DIL 805D动态淬火热膨胀...7000系铝合金因具备低密度、高强和高韧等优点而备受关注,工业中可通过多道次热变形来提升合金的综合性能,要获得接近理想状态下的铝合金性能,必须掌握多道次热变形工艺参数对组织演变造成的影响。本实验采用TA DIL 805D动态淬火热膨胀仪对7050铝合金进行等温热压缩,研究了变形温度、道次间隔时间和首应变对热压缩后的7050铝合金在流变应力、静态和动态软化机制、第二相及织构方面的影响,其中变形温度为360、400℃,应变速率为0.05 s^(-1),间隔时间为10、100 s,首道次应变量分别为0.2、0.4、0.6、0.8和1.0,总应变1.1。结果表明:7050铝合金在双道次热变形过程中发生了动态和静态软化,静态和动态软化机制都是再结晶。提高变形温度会促进再结晶进程,形成较强的P织构,首应变增加,动态软化效果显著,有利于动态再结晶,并且出现cube和R-cube织构,强度随首应变增大而加强。延长道次间隔时间会使织构大量聚集在α-取向线上。另外,合金经过热压缩后存在部分不溶相,但是不溶相的数量与分布与变形条件无关。展开更多
基金Project(51171209)supported by the National Natural Science Foundation of China
文摘The main methods of the second phase quantitative analysis in current material science researches are manual recognition and extracting by using software such as Image Tool and Nano Measurer. The weaknesses such as high labor intensity and low accuracy statistic results exist in these methods. In order to overcome the shortcomings of the current methods, the Ω phase in A1-Cu-Mg-Ag alloy is taken as the research object and an algorithm based on the digital image processing and pattern recognition is proposed and implemented to do the A1 alloy TEM （transmission electron microscope） digital images process and recognize and extract the information of the second phase in the result image automatically. The top-hat transformation of the mathematical morphology, as well as several imaging processing technologies has been used in the proposed algorithm. Thereinto, top-hat transformation is used for elimination of asymmetric illumination and doing Multi-layer filtering to segment Ω phase in the TEM image. The testing results are satisfied, which indicate that the Ω phase with unclear boundary or small size can be recognized by using this method. The omission of these two kinds of Ω phase can be avoided or significantly reduced. More Ω phases would be recognized （growing rate minimum to 2% and maximum to 400% in samples）, accuracy of recognition and statistics results would be greatly improved by using this method. And the manual error can be eliminated. The procedure recognizing and making quantitative analysis of information in this method is automatically completed by the software. It can process one image, including recognition and quantitative analysis in 30 min, but the manual method such as using Image Tool or Nano Measurer need 2 h or more. The labor intensity is effectively reduced and the working efficiency is greatly improved.
基金the National Key Laboratory of Metrology and Calibration Technology
文摘A finite domain time difference （FDTD） and second-derivative combined method is proposed for the evaluation of phase center in the Fresnel region of complex structure millimeter antennas. This method adopts FDTD＇s near to far field transformation to obtain the fields in Fresnel region and then applies the second-derivative method to calculate the phase center. The adoption of FDTD efficiently overcomes the difficulties arising from the existing calculation methods＇ requirements for the radiation analytical formula of some complex antennas, which makes the existing second-derivative method more applicable in engineering. Also, FDTD increases the precision owing to the superposition field calculation from its extrapolation. The correctness of this proposed method is certified with typical examples and the phase center in the Fresnel region of a microwave radiometry calibration corrugate horn antenna is evaluated with the key features.
文摘通过SEM、EDS和XRD,研究了稀土La添加量(0.1wt%、0.2wt%、0.4wt%、0.8wt%)对6082铝合金铸态组织和力学性能的影响。结果表明:稀土La可以明显细化合金晶粒、有效调控第二相并提高合金的力学性能。随着合金中稀土La含量的增加,合金晶粒尺寸先减小后增加,当稀土La含量为0.2wt%时合金的晶粒细化效果最好,此时合金的抗拉强度、屈服强度和伸长率均达到最高,分别为181 MPa、167 MPa和5.43%,明显优于未添加稀土La的合金抗拉强度、屈服强度和伸长率(128 MPa、87 MPa和4.68%)。稀土La的添加能将细长条状的β-Al Fe Si相调控成π状α-Al Si Fe相,大大降低了应力集中,从而有效提高合金的力学性能。
文摘7000系铝合金因具备低密度、高强和高韧等优点而备受关注,工业中可通过多道次热变形来提升合金的综合性能,要获得接近理想状态下的铝合金性能,必须掌握多道次热变形工艺参数对组织演变造成的影响。本实验采用TA DIL 805D动态淬火热膨胀仪对7050铝合金进行等温热压缩,研究了变形温度、道次间隔时间和首应变对热压缩后的7050铝合金在流变应力、静态和动态软化机制、第二相及织构方面的影响,其中变形温度为360、400℃,应变速率为0.05 s^(-1),间隔时间为10、100 s,首道次应变量分别为0.2、0.4、0.6、0.8和1.0,总应变1.1。结果表明:7050铝合金在双道次热变形过程中发生了动态和静态软化,静态和动态软化机制都是再结晶。提高变形温度会促进再结晶进程,形成较强的P织构,首应变增加,动态软化效果显著,有利于动态再结晶,并且出现cube和R-cube织构,强度随首应变增大而加强。延长道次间隔时间会使织构大量聚集在α-取向线上。另外,合金经过热压缩后存在部分不溶相,但是不溶相的数量与分布与变形条件无关。
