ISSN 0412-1961
CN 21-1139/TG
Started in 1956

#### Office

Featured Articles More>>
A new alloy design concept, high-entropy alloys (HEAs), has attracted increasing attentions and becomes a new research highlight recently. Different from traditional alloy design strategy which usually blends with one or two elements as the principal constituent and other minor elements for the furt. . .
 Acta Metall Sin, 2018 Vol. 54 (11): 1553-1566    DOI: 10.11900/0412.1961.2018.00372
Just Accepted More>>
 2020-03-27
 Influence of Secondary Orientation on Competitive Grain Growth PDF (2935KB)
 2020-03-27
 Effect of Heat Treatment on Microstructure and Properties of Nickel-based Powder Metallurgy Superalloy Processed by Selective Laser Melting PDF (5442KB)
 2020-03-25
 Investigation on meshless method for non-uniform heat transfer/solidification behavior of continuous casting round billet PDF (2164KB)
 2020-03-24
 Corrosion Behavior of Damaged Epoxy Coated Steel Bars under the Coupling Effect of Chloride Ion and Carbonization PDF (1207KB)
 2020-03-23
Current Issue More>>
 11 March 2020, Volume 56 Issue 3 Previous Issue
 Select Microstructural Evolution and Work Hardening Behavior of Fe-19Mn Alloy Containing Duplex Austenite and ε-Martensite WANG Shihong,LI Jian,GE Xin,CHAI Feng,LUO Xiaobing,YANG Caifu,SU Hang Acta Metall Sin. 2020, 56 (3): 311-320.   DOI: 10.11900/0412.1961.2019.00181 Abstract   HTML   PDF (17956KB) As the excellent combination of strength and ductility, the high manganese steel has been used in the manufacturing field of automobile, liquefied natural gas (LNG) ship and oil and gas exploitation. On the other hand, due to the good damping capacity within a certain Mn content range, it has also been used to make components on the machines to reduce vibration and noise. So high manganese steel is considered to be a structural and functional integrated material with great application prospects. Many factors can affect the mechanical properties and damping capacity, such as chemical composition, grain size and heat treatments. Among these, carbon concentration has a complicated influence on them. For example, a high carbon concentration will improve mechanical properties, but in return deteriorate damping capacity. In order to acquire a material with good damping capacity and suitable strength and ductility, ultralow carbon Fe-19Mn-0.0017C (mass fraction, %) alloy was designed. The microstructural evolution and mechanical properties of the alloy during tensile process were investigated by means of OM, EBSD, TEM, XRD and tension test. The results show that Fe-19Mn shows deformation-induced martensite transformation, which changes from γ-austenite→ε-martensite transformation to ε-martensite→α'-martensite transformation as the amount of deformation increases. Analysis of the strain hardening rate (ln(dσtrue/dεtrue)) combined with the fraction of constituent phases reveals that the transformation of ε-martensite→α'-martensite is more effective in improving work hardening rate than that of γ-austenite→ε-martensite. This is, on one hand, because of the lower strength of ε-martensite which is caused by the lack of carbon solution strengthening; and on the other hand, α'-martensite has higher hardness than ε-martensite, which can impede dislocation movement more effectively. In addition, {$101?2$}<$1?011$>ε deformation twins are formed to accommodate deformation of ε-martensite except for dislocation slip during tensile process. The combined action of transformation induced plasticity (TRIP) effects of γ-austenite→ε-martensite→α'-martensite transformation, dislocation slip of γ-austenite/ε-martensite/α'-martensite and {$101?2$}<$1?011$>ε deformation twinning makes Fe-19Mn with ultralow carbon concentration have an excellent combination of strength and ductility, whose tensile strength and total elongation can reach 722 MPa and 31%, respectively.
 Select Microstructures and Tensile Deformation Behavior of Directionally Solidified Mg-xGd-0.5Y Alloys SUN Heng,LIN Xiaoping,ZHOU Bing,ZHAO Shengshi,TANG Qin,DONG Yun Acta Metall Sin. 2020, 56 (3): 340-350.   DOI: 10.11900/0412.1961.2019.00229 Abstract   HTML   PDF (33665KB) The poor plastic deformation ability of magnesium alloy, resulted from its close-packed hexagonal structure and only two independent basal slip systems at room temperature that cannot meet the von Mises criterion, has extremely restricted its application. As the α-Mg dendrites grow along with the heat flow in directional solidification, the uniform columnar crystal structures obtained in Mg can effectively improve its mechanical properties. And the mechanical properties of the anisotropic magnesium alloys were heavily affected by the orientation controlled by the directional solidification parameters. In this work, the effects of Gd content (3.0%, 4.5%, 6.0%, mass fraction) on the microstructure and mechanical properties of directionally solidified Mg-xGd-0.5Y alloy were investigated. The tensile deformation behavior at room temperature was analyzed by EBSD technique. The results showed that the Mg-xGd-0.5Y alloys have a longitudinal grain boundary parallel to the heat flow direction and a preferential growth along the normal direction of the ($112?0$) plane at a withdrawn rate of 3 mm/min. The cross section of the columnar crystal was triangle or crisscross petal in shape, and the secondary branch gradually changed from three branches of 3.0%Gd to four branches of 6.0%Gd. The Mg-6.0Gd-0.5Y alloy with more columnar crystal growing along with <$224?3$> direction had higher tensile strength (107 MPa) and post-break elongation (32.56%) at room temperature, and its deformation mechanism was basal slipping and {$101?2$} extension twinning. When the crystal growth directions dispersed (concentrated on the <$1?21?0$> and <$224?3$>) in the Mg-3.0Gd-0.5Y alloy, it had low post-break elongation (14.88%) because of poor synergistic deformation ability, which have {$101?2$} extension twins and {$101?1$} contraction twins to accommodate strain.