Fe–Mn–Si‐based shape memory alloys are the most favorable for large‐scale applications owing to low cost, good workability, good machinability, and good weldability. However, polycrystalline ...Fe–Mn–Si‐based shape memory alloys have low recovery strains of only 2–3% after solution treatment, although monocrystalline ones reach a large recovery strain of ≈9%. This review gives an overview of the improvement of recovery strains for polycrystalline Fe–Mn–Si‐based shape memory alloys. It is proposed that two fundamental aspects, that is, composition design and microstructure design, shall be satisfied for obtaining large recovery strains of above 6%. Alloying compositions determining the ceiling of recovery strains shall follow three guidelines: (i) Si content is 5–6 wt%; (ii) 20 wt% ≤ Mn ≤ 32 wt%; (iii) addition of elements strongly strengthening austenite matrix. Microstructure design includes coarsening austenitic grains and reducing twin boundaries as far as possible together with introducing a high density of stacking faults and second phases of strengthening austenite.
Low cost Fe–Mn–Si‐based shape memory alloys are suitable for large‐scale applications. However, their recovery strains are only 2–3% in solution‐treated polycrystalline status. This review summarizes the origin of shape memory effect and the improvement history of recovery strains. It is concluded that two fundamental aspects, that is, composition design and microstructure design, shall be followed to achieve a large recovery strain of above 6%.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
To determine right thermodynamic parameters in calculating the stacking fault energy (SFE) in Fe-Mn-Si-C high manganese steels, deformation mechanisms of several Fe-Mn-Si-C high manganese steels were ...studied, and their SFEs were calculated through thermodynamic model using two sets of parameters, respectively. The results showed that the parameters of Scientific Group Thermodata Europe (SGTE) could be used to calculate the SFE and predict the deformation mechanisms of Fe-Mn-Si-C steels properly. The addition of Si significantly lowered their SFE rise due to the increase of Mn content. The increase of C content strongly raised their SFE but lowered their SFE rise due to the increase of Mn content. When the Mn content is lower, their SFE first increased with raising Si content up to a critical value, over which they decreased with Si content. This critical value of Si dropped with the rise in Mn and C contents. The increase of Mn content had little effect on the SFE of the Fe-xMn-6Si-1C steels.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
To improve the low work hardening capacity of Hadfield steel at low stress, the effect of stacking fault energy (SFE) on the microstructures and the work hardening behaviors of the Fe–Mn–Si–C high ...manganese steels were investigated by varying the silicon and carbon contents. The work hardening rates of the Fe–17Mn–Si–C steels with lower SFE were higher than that of the Hadfield steel at the strain below 0.28. The reason was that the amount of deformation-induced ε-martensite or mechanical twins was higher in the Fe–17Mn–Si–C steels than in the Hadfield steel due to their earlier onset. The work hardening rate of the Fe–17Mn–Si–C steels increased with decreasing the SFE because the rate of the formation and the amounts of martensite and twins increased with lowering the SFE.
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•The Fe–Mn–Si–C steels show a higher work hardening rate than Hadfield steel does.•More martensite account for higher work hardening rates in the Fe–Mn–Si–C steels.•The lower the stacking fault energy is, the earlier the onset of martensite is.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Effects of a long annealing up to 10 h were investigated on damping capacity and phase evolutions in FeMn-based alloys. The damping capacity in the Fe17.5Mn alloy rose with the annealing time. A ...highest damping capacity was obtained in the Fe16.5Mn10.5Cr alloy after 2 h annealing. The highest damping capacity was comparable in Fe17.5Mn and Fe16.5Mn10.5Cr alloys. A positive relationship between the damping capacity and the stacking faults existed in both the Fe17.5Mn and Fe16.5Mn10.5Cr alloys annealed for above 2 h. To reduce the amount of α′-martensites was favourable to the further improvement of damping capacity. The α′-martensites clustered locally in the Fe17.5Mn alloy, but they distributed inside the ϵ-martensite bands in the Fe16.5Mn10.5Cr alloy.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Background
Microvascular invasion (MVI) is a risk factor for tumor recurrence after hepatectomy in hepatocellular carcinoma (HCC) patients.
Objective
This study aimed to investigate the efficacy and ...safety of postoperative adjuvant transarterial infusion chemotherapy (TAI) with the FOLFOX regimen for HCC patients with MVI.
Methods
In this prospective, phase III, randomized, open-label, controlled clinical trial, HCC patients with histologically confirmed MVI were randomly assigned (1:1) after hepatectomy to receive either one to two cycles of adjuvant TAI (AT group) or follow-up without any adjuvant treatment (FU group). The primary endpoint was disease-free survival (DFS), while secondary endpoints were overall survival (OS) and safety.
Results
Between June 2016 and April 2019, 127 patients were randomly assigned to the AT group (
n
= 63) or FU group (
n
= 64). Clinicopathological characteristics of the two groups were well-balanced. The 6-, 12-, and 18-month OS rates for the AT group were 100.0%, 97.7%, and 97.7%, respectively, and 94.5%, 89.6%, and 78.5% for the FU group, respectively. The 6-, 12-, and 18-month DFS rates for the AT and FU groups were 84.7%, 61.8%, and 58.7%, and 62.9%, 48.1%, and 38.6%, respectively. OS and DFS were significantly better in the AT group than in the FU group (
p
= 0.037 and 0.023, respectively). No patients in the AT group experienced grade 3 or more severe adverse events.
Conclusions
Adjuvant TAI after hepatectomy may bring survival benefits to HCC patients with MVI.
Trial registration
Trial number: NCT03192618.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In order to improve the work hardening capacity under low stresses and the yield strength of conventional Hadfield steels, the effects of Si on the microstructure and work hardening behavior of the ...Fe‒17Mn‒1.1C‒xSi steels under both quasi-static tensile and low load impact are investigated. It is shown that the increase of the Si contents remarkably improves the yield strength by 36 MPa per 1 wt% Si in the investigated steel system without significant sacrifice of ductility. The decreasing effect of Si on the stacking fault energy is strongly affected by carbon, although the variation of carbon content was small. This led to the unexpected similar stacking fault energy between 1Si and 2Si steel. With the increase of the Si contents for the steels, the critical strain for the onset of mechanical twinning was lowered, which was controlled by the cooperation between the stacking fault energy and solid solution strengthening of Si. This resulted in the earlier initiation of mechanical twins and an increase in the twin volume fraction. Therefore, the work hardening capacities under both quasi-static tensile and low load impact tests were enhanced. It was also found that the impact deformation decreased as more mechanical twins absorbed the impact energy.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Ductile Cu–Al–Mn shape memory alloys obtain the damping capacity through the movement of martensite boundaries. To reduce the number of vacancies at martensite boundaries can improve their damping ...capacity. Our results showed that Ni alloying could remarkably suppress the vacancy movement during the process of cooling from high temperature and heating as well as ageing. The Cu-18.0Al-8.4Mn-2.5Ni alloy showed remarkably higher damping capacity than the Cu-18.0Al-9.4Mn alloy did due to the reduced vacancies at martensite boundaries by the Ni alloying, regardless of the direct quenching, up-quenching, and step-quenching. The occurrence of martensitic stabilization could rationalize the lower improvement of damping capacity in the up-quenched Cu-18.0Al-9.4Mn alloy. The present results also further confirmed that the original number of vacancies at the martensite boundaries determined the occurrence of martensitic stabilization.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this work, we report a (Ni50.1Ti34.9Hf15)85Nb15 alloy that shows excellent cold workability and good high-temperature shape memory effect. The as-cast sample shows eutectic microstructure ...consisting of β-Nb and the NiTiHf(Nb) matrix. The homogenized (Ni50.1Ti34.9Hf15)85Nb15 alloy shows high compressive fracture strain of 40% and excellent cold-rolling reduction ratio of 80%. It is suggested that the formation of (semi-) coherent β-Nb is the main reason on improving the ductility of NiTiHf alloy. After solution treatment, the material shows a high martensitic transformation start temperature of 146 °C, and a maximum shape memory effect strain of 2.3%. This work demonstrates that (Ni50.1Ti34.9Hf15)85Nb15 alloy with good cold workability and high-temperature shape memory effect may provide new opportunities for applications.
•Microstructure comprises (semi-) coherent β-Nb and NiTiHf(Nb) matrix is obtained.•Coherent β-Nb acts as nucleation and promotes martensitic transformation.•Compressive fracture strain 40% and cold-rolling reduction ratio 80% are obtained.•Martensitic transformation start temperature of 146 °C is obtained.•A maximum shape memory effect strain of 2.3% is achieved.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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