An Al-3Ti-0.2C-1RE grain refiner was prepared by in-situ reaction method.The microstructure was investigated by optical microscopy(OM),scanning electron microscopy(SEM) equipped with energy-dispersive spectrometry(EDS...An Al-3Ti-0.2C-1RE grain refiner was prepared by in-situ reaction method.The microstructure was investigated by optical microscopy(OM),scanning electron microscopy(SEM) equipped with energy-dispersive spectrometry(EDS) and X-ray diffraction(XRD).The results show that the Al-3Ti-0.2C-1RE grain refiner is composed of α-Al,TiAl3,TiC and Ti2 Al20 Ce phases.Compared with Al-3Ti-0.2C refiner,the morphology of TiAl3 phase is changed and Ti2 Al20 Ce phases form with the addition of RE.Accordingly,the refining performance is improved.The phase forming process of the refiner is as follows: Blocky Ti2 Al20 Ce and fine blocky TiAl3 form in the melt at the initial stage of reaction,then the fine blocky TiAl3 gradually disappears,and the blocky Ti2 Al20 Ce grows bigger with the increase of holding time.The predominant mechanism to synthesize TiC particles is the reaction between high concentration of solute Ti atoms and graphite particles.展开更多
In the present work, scandium elements with a series of contents(0.06 wt.%, 0.10 wt.%, 0.14 wt.%,0.17 wt.%, 0.20 wt.% and 0.25 wt.%) were added in a high Zn-containing Al-Zn-Mg-Cu-Zr alloy and the corresponding as-cas...In the present work, scandium elements with a series of contents(0.06 wt.%, 0.10 wt.%, 0.14 wt.%,0.17 wt.%, 0.20 wt.% and 0.25 wt.%) were added in a high Zn-containing Al-Zn-Mg-Cu-Zr alloy and the corresponding as-cast microstructure characteristics including grains and phases were thoroughly investigated. The results indicated that fine grain boundaries existed in these alloys and fine MgZn2phases discontinuously distributed on them. Besides,AlZnMgCu eutectic phases and Sc, Zr-containing phases with flocculent morphology were observed. As scandium contents vary from 0.06 wt.% to 0.17 wt.%, the average grain size continuously decreased and its equiaxial characteristics were strengthened. Meanwhile, the content of AlZnMgCu eutectic phase showed a decrease trend. When scandium contents were 0.20 wt.% and 0.25 wt.%, no further enhancement on grain refinement was observed, so as to the reduction of AlZnMgCu eutectic phase content. Besides, Sc, Zr-containing phases with blocky morphology were observed and the alloy with a scandium content of 0.25 wt.% possessed a larger amount of blocky Sc, Zr-containing phase than the alloy with a scandium content of 0.20 wt.%. Grain refinement and reduction of AlZnMgCu eutectic phase content associated with scandium addition were discussed.展开更多
The uniform experiment design is an effective way of optimizing technology scheme for refining the grain size during multistage deformation. In this paper, it is adopted to evaluate the effect of each technology param...The uniform experiment design is an effective way of optimizing technology scheme for refining the grain size during multistage deformation. In this paper, it is adopted to evaluate the effect of each technology parameter on final grain size of AISI H13 hot work tool steel during multistage deformation. It has been verified that the technology scheme for refining the final grain size can be determined rapidly and efficiently with the aid of the uniform design. The results show that the deformation parameters and the intermission time after deformation of the first stage affect the final grain size remarkably. For AISI H13 hot work tool steel, the final grain size can be refined notably when deformation parameters for the first stage are set as follows: a deformation temperature range of 1?025 1?085 ℃; a true strain of above 0.26 and the interpass time between the first and the second stage of deformation less than 10 s.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
基金Project(51174177)supported by the National Natural Science Foundation of China
文摘An Al-3Ti-0.2C-1RE grain refiner was prepared by in-situ reaction method.The microstructure was investigated by optical microscopy(OM),scanning electron microscopy(SEM) equipped with energy-dispersive spectrometry(EDS) and X-ray diffraction(XRD).The results show that the Al-3Ti-0.2C-1RE grain refiner is composed of α-Al,TiAl3,TiC and Ti2 Al20 Ce phases.Compared with Al-3Ti-0.2C refiner,the morphology of TiAl3 phase is changed and Ti2 Al20 Ce phases form with the addition of RE.Accordingly,the refining performance is improved.The phase forming process of the refiner is as follows: Blocky Ti2 Al20 Ce and fine blocky TiAl3 form in the melt at the initial stage of reaction,then the fine blocky TiAl3 gradually disappears,and the blocky Ti2 Al20 Ce grows bigger with the increase of holding time.The predominant mechanism to synthesize TiC particles is the reaction between high concentration of solute Ti atoms and graphite particles.
基金Projects(2020YFB0311400ZL, 2020YFF0218202) supported by the National Key R&D Program of ChinaProject supported by Youth Fund Project of GRINM Group Co.,Ltd.,China。
文摘In the present work, scandium elements with a series of contents(0.06 wt.%, 0.10 wt.%, 0.14 wt.%,0.17 wt.%, 0.20 wt.% and 0.25 wt.%) were added in a high Zn-containing Al-Zn-Mg-Cu-Zr alloy and the corresponding as-cast microstructure characteristics including grains and phases were thoroughly investigated. The results indicated that fine grain boundaries existed in these alloys and fine MgZn2phases discontinuously distributed on them. Besides,AlZnMgCu eutectic phases and Sc, Zr-containing phases with flocculent morphology were observed. As scandium contents vary from 0.06 wt.% to 0.17 wt.%, the average grain size continuously decreased and its equiaxial characteristics were strengthened. Meanwhile, the content of AlZnMgCu eutectic phase showed a decrease trend. When scandium contents were 0.20 wt.% and 0.25 wt.%, no further enhancement on grain refinement was observed, so as to the reduction of AlZnMgCu eutectic phase content. Besides, Sc, Zr-containing phases with blocky morphology were observed and the alloy with a scandium content of 0.25 wt.% possessed a larger amount of blocky Sc, Zr-containing phase than the alloy with a scandium content of 0.20 wt.%. Grain refinement and reduction of AlZnMgCu eutectic phase content associated with scandium addition were discussed.
基金TheNationalNaturalScienceFoundationofChina (No .5 0 0 75 0 5 3)
文摘The uniform experiment design is an effective way of optimizing technology scheme for refining the grain size during multistage deformation. In this paper, it is adopted to evaluate the effect of each technology parameter on final grain size of AISI H13 hot work tool steel during multistage deformation. It has been verified that the technology scheme for refining the final grain size can be determined rapidly and efficiently with the aid of the uniform design. The results show that the deformation parameters and the intermission time after deformation of the first stage affect the final grain size remarkably. For AISI H13 hot work tool steel, the final grain size can be refined notably when deformation parameters for the first stage are set as follows: a deformation temperature range of 1?025 1?085 ℃; a true strain of above 0.26 and the interpass time between the first and the second stage of deformation less than 10 s.
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。
