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金屬頂刊雙語導(dǎo)讀丨Scripta Mater. Vol.207, 15 Jan. 2022（下）

2021-12-11 來源：GS_Metals

 

本期包含金屬材料領(lǐng)域論文13篇，涵蓋了增材制造、鎂合金、高溫合金、馬氏體等，國內(nèi)科研單位包括西安交通大學(xué)、天津大學(xué)、中國科學(xué)院金屬研究所等（通訊作者單位）。

 

Vol. 207 目錄

1. Alloy design strategy for microstructural-tailored scandium-modified aluminium alloys for additive manufacturing

用于增材制造的微結(jié)構(gòu)定制鈧改性鋁合金的合金設(shè)計(jì)策略

 

2. Influence of grain size and grain boundary misorientation on the fatigue crack initiation mechanisms of textured AZ31 Mg alloy

晶粒尺寸和晶界取向差對織構(gòu)AZ31鎂合金疲勞裂紋萌生機(jī)制的影響

 

3. Influence of the microstructural homogeneity on the high-temperature oxidation behavior of a single crystalline Ni-base superalloy

顯微組織均勻性對鎳基單晶高溫合金高溫氧化行為的影響

 

4. Enhancing reversible entropy change of all-d-metal Ni37.5Co12.5Mn35Ti15 alloy by multiple external fields

多外場增強(qiáng)全d金屬Ni37.5Co12.5Mn35Ti15合金可逆熵變

 

5. Effect of microstructure heterogeneity on the mechanical properties of friction stir welded reduced activation ferritic/martensitic steel

顯微組織異質(zhì)性對攪拌摩擦焊還原活化鐵素體/馬氏體鋼力學(xué)性能的影響

 

6. Hydrogen-assisted failure in Inconel 718 fabricated by laser powder bed fusion: The role of solidification substructure in the embrittlement

激光粉床熔化制造的Inconel 718氫輔助失效：凝固亞結(jié)構(gòu)在脆化中的作用

 

7. Synthesis of high-entropy alloy thin films via grain boundary diffusion–assisted solid-state alloying

通過晶界擴(kuò)散輔助固態(tài)合金化合成高熵合金薄膜

 

8. Deformation twinning-induced dynamic recrystallization during laser powder bed fusion

激光粉床熔融過程中變形孿晶誘導(dǎo)的動(dòng)態(tài)再結(jié)晶

 

9. Mechanical response of the constrained nanostructured layer in heterogeneous laminate

異質(zhì)層壓板中受限納米結(jié)構(gòu)層的機(jī)械響應(yīng)

 

10. Prediction of growth velocity of undercooled multicomponent metallic alloys using a machine learning approach

使用機(jī)器學(xué)習(xí)方法預(yù)測過冷多組分金屬合金的生長速度

 

11. Martensitic transformation within nanotwins enhances fatigue damage resistance of a nanotwinned austenitic stainless steel

納米孿晶內(nèi)的馬氏體相變增強(qiáng)了納米孿晶奧氏體不銹鋼的抗疲勞損傷能力

 

12. In situ transmission electron microscopy investigation of nucleation of GP zones under natural aging in Al-Zn-Mg alloy

Al-Zn-Mg合金自然時(shí)效下GP區(qū)形核的原位透射電鏡研究

 

13. Grain boundary segregation and its implications regarding the formation of the grain boundary α phase in the metastable β-Titanium Ti–5Al–5Mo–5V–3Cr alloy

亞穩(wěn)態(tài)β-鈦Ti-5Al-5Mo-5V-3Cr合金中晶界偏析及其對晶界α相形成的影響

 

 

SCRIPTA

Vol. 207, 15 Jan. 2022, 114277

1. Alloy design strategy for microstructural-tailored scandium-modified aluminium alloys for additive manufacturing

用于增材制造的微結(jié)構(gòu)定制鈧改性鋁合金的合金設(shè)計(jì)策略

 

D. Schimback?, P. Mair, M. Bartl, F. Palm, G. Leichtfried, S. Mayer, P.J. Uggowitzer, S. Pogatscher

D. Schimback: david-erich.schimbaeck@airbus.com

https://doi.org/10.1016/j.scriptamat.2021.114277

 

摘要

為了充分發(fā)揮增材制造技術(shù)的潛力，有必要通過智能合金設(shè)計(jì)策略使材料適應(yīng)工藝。為此，為了推導(dǎo)和研究各種材料概念，研究了Sc改性鋁合金在激光粉末床熔合生產(chǎn)過程中的微觀結(jié)構(gòu)演變。添加Mg作為主要元素（Al-4.4Mg-0.8Sc-0.3Zr-0.5Mn）會(huì)產(chǎn)生雙峰微觀結(jié)構(gòu)。相比之下，如果添加Cr作為主要元素（Al-2.6Cr-0.7Sc-0.3Zr），則外延晶粒生長會(huì)跨越多個(gè)焊道，從而產(chǎn)生明顯的織構(gòu)；添加Ti作為主要元素（Al-1Ti-1Sc-0.4Zr）會(huì)產(chǎn)生均勻的超細(xì)晶粒組織。這些微觀結(jié)構(gòu)之間的差異源于晶粒生長限制因素和溶質(zhì)與初級沉淀結(jié)構(gòu)的相互作用。因此，對關(guān)鍵冶金因素的精確控制產(chǎn)生了可以根據(jù)某些要求量身定制的新型材料。

向上滑動(dòng)閱覽英文摘要

To exploit the full potential of the additive layer manufacturing technique it is necessary to adapt the material to the process via a smart alloy design strategy. To this end, in order to derive and investigate various material concepts, the microstructural evolution of Sc-modified Al alloys was studied during the course of their production by laser powder bed fusion. Adding Mg as the main element (Al-4.4Mg-0.8Sc-0.3Zr-0.5Mn) generates an already-familiar bimodal microstructure. In contrast, if Cr is added as the main element (Al-2.6Cr-0.7Sc-0.3Zr), epitaxial grain growth takes place across several weld tracks, resulting in a distinct texture; and adding Ti as the main element (Al-1Ti-1Sc-0.4Zr) produces a uniform ultrafine-grained microstructure. The differences between these microstructures arise from interactions of the grain growth restriction factors and the solute with the primary precipitation structure. Thus, the precise manipulation of key metallurgical factors leads to novel materials which can be tailor-made for certain requirements.

 

 

SCRIPTA

Vol. 207, 15 Jan. 2022, 114304

2. Influence of grain size and grain boundary misorientation on the fatigue crack initiation mechanisms of textured AZ31 Mg alloy

晶粒尺寸和晶界取向差對織構(gòu)AZ31鎂合金疲勞裂紋萌生機(jī)制的影響

 

Abbas Jamali, Anxin Ma, Javier LLorca?

Javier LLorca: javier.llorca@upm.es

https://doi.org/10.1016/j.scriptamat.2021.114304

 

摘要

對織構(gòu)AZ31B-O鎂合金沿軋制方向進(jìn)行完全反向、應(yīng)變控制的循環(huán)變形，并在50次循環(huán)后（約占疲勞壽命的33%）分析變形和裂紋萌生機(jī)制。在2100個(gè)晶粒中的538個(gè)中發(fā)現(xiàn)了對應(yīng)于金字塔滑移或拉伸孿晶的不同變形帶。滑移軌跡分析表明，72.3%是錐體滑移帶，18.4%是孿晶邊界。僅在9.1%的具有變形帶的晶粒中發(fā)現(xiàn)了金字塔滑移和孿晶。50次循環(huán)后裂紋普遍存在。在約15%的小晶粒（< 20 µm）中發(fā)現(xiàn)了晶界裂紋，它們主要與大角度晶界（>40º）相關(guān)。還發(fā)現(xiàn)裂紋是由平行于大晶粒（>45 µm）的金字塔滑移帶或?qū)\晶界的穿晶裂紋引起的。大多數(shù)（>60%）大晶粒在50次循環(huán)后出現(xiàn)穿晶裂紋。

向上滑動(dòng)閱覽英文摘要

The deformation and crack initiation mechanisms were analyzed in a textured AZ31B-O Mg alloy subjected to fully-reversed, strain-controlled cyclic deformation along the rolling direction after 50 cycles (approximately 33% of the fatigue life). Distinct deformation bands corresponding to pyramidal slip or tensile twins were found in 538 grains out of 2100 grains. Slip trace analysis showed that 72.3% were pyramidal slip bands and 18.4% were twin boundaries. Both pyramidal slip and twinning was only found in 9.1% of the grains with deformation bands. Cracking was widespread after 50 cycles. Grain boundary cracks were found in ≈15% of the small grains (< 20 µm) and they were mainly associated with high angle grain boundaries (>40º). Cracking was also found to occur by transgranular cracks parallel to the pyramidal slip bands or twin boundaries in large grains (>45 µm). The majority (>60%) of these large grains presented transgranular cracks after 50 cycles.

 

 

SCRIPTA

Vol. 207, 15 Jan. 2022, 114224

3. Influence of the microstructural homogeneity on the high-temperature oxidation behavior of a single crystalline Ni-base superalloy

顯微組織均勻性對鎳基單晶高溫合金高溫氧化行為的影響

 

J. Pistor?, S.P. Hagen?, S. Virtanen?, C. Korner?

J. Pistor: julian.pistor@fau.de

S.P. Hagen: sebastian.p.hagen@fau.de

S. Virtanen: virtanen@ww.uni-erlangen.de

C. Korner: carolin.koerner@fau.de

https://doi.org/10.1016/j.scriptamat.2021.114224

 

摘要

通過選擇電子束熔化（SEBM）進(jìn)行的增材制造最近被證明是一種用于生產(chǎn)CMSX-4單晶（SX）鎳基高溫合金的有趣技術(shù)。本研究的目的是比較SX SEBM樣品與由Bridgman熔模鑄造獲得的傳統(tǒng)試樣的高溫抗氧化性。因此，TGA重量分析在850和1050 °C下在空氣中進(jìn)行100小時(shí)。由于在氧化之前進(jìn)行固溶退火，在SEBM試樣中，凝固引起的元素偏析可以完全均勻化，而對于傳統(tǒng)試樣仍然很明顯。由于殘留元素偏析，在氧化過程中出現(xiàn)了不均勻的氧化皮，在枝晶區(qū)域表現(xiàn)出高于平均水平的氧化皮厚度。因此，在存在偏析的情況下，TGA顯示出更高的質(zhì)量增加。總之，對于均質(zhì)SEBM樣品觀察到更好的高溫抗氧化性。

向上滑動(dòng)閱覽英文摘要

Additive manufacturing by means of selective electron beam melting (SEBM) was recently demonstrated as an intriguing technique for the generation of single crystalline (SX) CMSX-4, a commercial Ni-base superalloy. The objective of this study is to compare the high-temperature oxidation resistance of SX SEBM-samples to their conventional counterparts which are derived by Bridgman investment casting. Therefore, time-resolved isothermal gravimetric analysis (TGA) was conducted at 850 and 1050 °C in synthetic air for 100 h. Due to solution annealing prior to oxidation, solidification induced elemental segregations could be homogenized completely in case of the SEBM-material, whereas they remained apparent for the conventional Bridgman samples. With residual elemental segregations inhomogeneous oxide scales emerged during exposure, exhibiting above-average scale thicknesses upon dendritic regions. Consequently, TGA revealed a higher mass gain in case of present segregations. In conclusion, a better high temperature oxidation resistance is observed for the homogeneous SEBM material.

 

 

SCRIPTA

Vol. 207, 15 Jan. 2022, 114303

4. Enhancing reversible entropy change of all-d-metal Ni37.5Co12.5Mn35Ti15 alloy by multiple external fields

多外場增強(qiáng)全d金屬Ni37.5Co12.5Mn35Ti15合金可逆熵變

 

Yao Liu?, Andong Xiao, Tianzi Yang, Zhitong Xu, Xianglong Zhou, Tianyu Ma?

Yao Liu: liuyao12@xjtu.edu.cn （西安交通大學(xué)）

Tianyu Ma: matianyu@xjtu.edu.cn （西安交通大學(xué)）

https://doi.org/10.1016/j.scriptamat.2021.114303

 

摘要

引入多個(gè)外場增強(qiáng)全d金屬Ni37.5Co12.5Mn35Ti15合金的可逆熵變。研究表明，對于0.01到5 T的磁場變化，可逆熵變可以從8.9大幅增加到24.1 J kg-1K-1。透射電鏡對Ni37.5Co12.5Mn35Ti15結(jié)構(gòu)轉(zhuǎn)變的研究表明，磁結(jié)構(gòu)轉(zhuǎn)變溫度隨著磁場的變化以-1.4K T-1的速率降低，并隨著靜水壓力以+5K k bar-1 的速率增加，從而為促進(jìn)多場循環(huán)下的可逆熵變提供了條件。

向上滑動(dòng)閱覽英文摘要

The multiple external fields have been introduced to enhance the reversible entropy change of all-d-metal Ni37.5Co12.5Mn35Ti15 alloy. Our studies reveal that the reversible entropy change can be largely increased from 8.9 J kg−1K−1 to 24.1 J kg−1K−1 for a magnetic field change of 0.01 T to 5 T. The combined investigations of structural transition by transmission electron microscopy and magneto-strain reveal a strong coupling between magnetism and volume in the alloy, due to which, the magneto-structural transition temperature of Ni37.5Co12.5Mn35Ti15 decreases with the magnetic field by a rate of -1.4K T−1, and increases with the hydrostatic pressure by a rate +5K kbar−1, thus providing the condition for the promotion of reversible entropy change under multiple fields cycling.

 

 

SCRIPTA

Vol. 207, 15 Jan. 2022, 114306

5. Effect of microstructure heterogeneity on the mechanical properties of friction stir welded reduced activation ferritic/martensitic steel

顯微組織異質(zhì)性對攪拌摩擦焊還原活化鐵素體/馬氏體鋼力學(xué)性能的影響

 

Shengli Li, Napat Vajragupta, Abhishek Biswas, Wenshen Tang, Hao Wang, Aleksander kostka, Xinqi Yang?, Alexander Hartmaier

Xinqi Yang: xqyang@tju.edu.cn （天津大學(xué)）

https://doi.org/10.1016/j.scriptamat.2021.114306

 

摘要

本文研究了攪拌摩擦焊還原活化鐵素體/馬氏體鋼不同區(qū)域的顯微硬度分布，并通過電子背散射分析將其與各個(gè)區(qū)域的分級馬氏體顯微組織相關(guān)聯(lián)。結(jié)果表明，攪拌摩擦焊過程中不同亞區(qū)的原始奧氏體晶粒尺寸、包塊尺寸和寬度的變化受峰值溫度和有效應(yīng)變速率的影響。顯微硬度的分布與在不同區(qū)域觀察到的幾何必要位錯(cuò)密度直接相關(guān)。

向上滑動(dòng)閱覽英文摘要

The microhardness distribution in the different zones of a friction stir welded reduced activation ferritic/martensitic steel has been investigated and correlated to the hierarchical martensitic microstructure in the respective zones, characterized by electron backscatter diffraction orientation analysis. It is found that the variation of prior austenite grain size, packet size, and block width in different subzones is influenced by the peak temperature and effective strain rate during the friction stir welding process. The distribution of the microhardness correlates directly with the geometrically necessary dislocation density observed in the different zones.

 

 

SCRIPTA

Vol. 207, 15 Jan. 2022, 114308

6. Hydrogen-assisted failure in Inconel 718 fabricated by laser powder bed fusion: The role of solidification substructure in the embrittlement

激光粉床熔化制造的Inconel 718氫輔助失效：凝固亞結(jié)構(gòu)在脆化中的作用

 

Dong-Hyun Lee?, Yakai Zhao, Soo Yeol Lee, Dirk Ponge, Eric A. Jagle

Dong-Hyun Lee: dhlee@cnu.ac.kr

https://doi.org/10.1016/j.scriptamat.2021.114308

 

摘要

通過一系列拉伸實(shí)驗(yàn)研究了氫氣對激光粉床熔融法制備的Inconel 718力學(xué)行為的影響。樣品經(jīng)過兩種不同方式熱處理，即直接實(shí)效（DA）和均勻化加實(shí)效（HA）。詳細(xì)的微觀結(jié)構(gòu)表征表明，在DA樣品中存在包括高密度位錯(cuò)和沉淀物的凝固亞結(jié)構(gòu)，而HA樣品沒有這種亞結(jié)構(gòu)。DA樣品表現(xiàn)出相對較高的強(qiáng)度，但抗氫脆性較低。通過對氫輔助裂紋的統(tǒng)計(jì)分析，證明DA樣品的嚴(yán)重氫脆是由于大部分氫輔助晶間裂紋是在沒有滑移定位幫助的情況下發(fā)生的。這些結(jié)果是根據(jù)熱處理后微觀結(jié)構(gòu)的變化及其對氫捕獲位點(diǎn)的影響進(jìn)行討論的。

向上滑動(dòng)閱覽英文摘要

The influence of hydrogen on the mechanical behavior of Inconel 718 fabricated by laser powder-bed-fusion was investigated through a series of tensile experiments. Samples subjected to two different post-fabrication heat treatments, viz. direct aging (DA) and homogenization plus aging (HA), were tested. Detailed microstructural characterization showed that a solidification substructure including a high density of dislocations and precipitates prevails in the DA sample while the HA sample is free from such a substructure. The DA sample exhibited a comparatively higher strength, but a lower resistance to hydrogen embrittlement. By recourse to a statistical analysis of the hydrogen-assisted cracks, the severe hydrogen embrittlement of the DA sample was proven to be due to the significant portion of hydrogen-assisted intergranular cracks that occurred without the aid of slip localization. These results are discussed in terms of the changes in microstructure upon heat treatments, and their influences on the hydrogen trapping sites.

 

 

SCRIPTA

Vol. 207, 15 Jan. 2022, 114302

7. Synthesis of high-entropy alloy thin films via grain boundary diffusion–assisted solid-state alloying

通過晶界擴(kuò)散輔助固態(tài)合金化合成高熵合金薄膜

 

Seungjin Nam, Sang Jun Kim, Moon J. Kim, Manuel Quevedo-Lopez, Jun Yeon

Hwang, Eun Soo Park?, Hyunjoo Choi?

Eun Soo Park: espark@snu.ac.kr

Hyunjoo Choi: hyunjoo@kookmin.ac.kr

https://doi.org/10.1016/j.scriptamat.2021.114302

 

摘要

在這項(xiàng)工作中，通過Al6(CoCrFeNi)94多層膜的固態(tài)合金化成功合成了具有面心立方結(jié)構(gòu)的CoCrFeNi基固溶體高熵合金薄膜，并通過優(yōu)化Al含量以防止任何氧化反應(yīng)。系統(tǒng)地研究了多層薄膜中的微觀結(jié)構(gòu)和相演變，以了解合金化行為。有趣的是，合金元素可以擴(kuò)散到薄膜層中，即使是那些具有非連接界面的層，這是由于納米結(jié)構(gòu)柱狀晶粒的存在，可通過晶界發(fā)生擴(kuò)散。因此，這些晶界充當(dāng)合金元素的擴(kuò)散路徑網(wǎng)絡(luò)，在整個(gè)多層膜中均質(zhì)化并形成反應(yīng)相，而不管熱力學(xué)和動(dòng)力學(xué)的預(yù)測如何。因此，晶界擴(kuò)散輔助固態(tài)合金化可用于通過僅控制多層膜中的層厚度來合成用于各種多組分合金系統(tǒng)的高熵合金薄膜。

向上滑動(dòng)閱覽英文摘要

Herein, CoCrFeNi high-entropy alloy thin films were successfully synthesized via solid-state alloying from Al6(CoCrFeNi)94 multilayer films, forming a CoCrFeNi-based solid solution phase with a face-centered cubic structure by optimizing Al content to prevent any oxide reaction. The microstructural and phase evolutions in the multilayer films were systematically investigated to understand the alloying behavior. Interestingly, it can be evaluated that the alloying elements could be diffused into layers, even those with nonconnected interfaces, through the grain boundaries owing to the presence of nanostructured columnar grains. Thus, these grain boundaries act as a network of diffusion paths for alloying elemental atoms to be homogenized throughout multilayer films and form the reactive phase regardless of the thermodynamic and kinetic prediction. Consequently, grain boundary diffusion–assisted solid-state alloying can be used to synthesize high-entropy alloy thin films for various multicomponent alloy systems by only controlling the layer thickness in multilayer films.

 

 

SCRIPTA

Vol. 207, 15 Jan. 2022, 114307

8. Deformation twinning-induced dynamic recrystallization during laser powder bed fusion

激光粉床熔融過程中變形孿晶誘導(dǎo)的動(dòng)態(tài)再結(jié)晶

 

Hossein Eskandari Sabzi, Xiao-Hui Li, Chi Zhang, Hanwei Fu, David San-Martin, Pedro E.J. Rivera-Diaz-del-Castillo?

Pedro E.J. Rivera-Diaz-del-Castillo: p.rivera1@lancaster.ac.uk

https://doi.org/10.1016/j.scriptamat.2021.114307

 

摘要

在使用各種工藝參數(shù)制造奧氏體不銹鋼的激光粉床融合（LPBF）過程中觀察到納米孿晶的形成。透射電鏡被用來去揭示這種孿晶的本質(zhì)，這是由于LPBF固有的高應(yīng)變快速凝固而形成的。動(dòng)態(tài)再結(jié)晶（DRX）在LPBF期間也被激活，并由變形納米孿晶誘導(dǎo)。同時(shí)，提出了一個(gè)恒溫模型來確定孿生誘導(dǎo)DRX的臨界條件，并通過實(shí)驗(yàn)結(jié)果驗(yàn)證了該模型。這種建模方法提供了一種對奧氏體不銹鋼進(jìn)行微觀結(jié)構(gòu)設(shè)計(jì)的方法，用于對高強(qiáng)度和延展性要求的應(yīng)用。

向上滑動(dòng)閱覽英文摘要

Nanotwin formation is observed during laser powder bed fusion (LPBF) of austenitic stainless steels fabricated with various process parameters. Transmission electron microscopy was employed to reveal the nature of such twins, which are formed due to the high strain rapid solidification inherent to LPBF. Dynamic recrystallization (DRX) was also activated during LPBF, and induced by the deformation nanotwins. A thermostatistical model is proposed to determine the critical conditions for twinning-induced DRX; the model is validated with the reported experimental results. This modelling approach offers a method to microstructurally engineer austenitic stainless steels for potential applications needing high strength and ductility.

 

 

SCRIPTA

Vol. 207, 15 Jan. 2022, 114310

9. Mechanical response of the constrained nanostructured layer in heterogeneous laminate

異質(zhì)層壓板中受限納米結(jié)構(gòu)層的機(jī)械響應(yīng)

 

Hanfei Wang, Yueguang Wei?, Zhifu Zhao, ZHongya Lin, Fengjiao Guo, Qian Cheng, Chongxiang Huang?, Yuntian Zhu

Yueguang Wei: weiyg@pku.edu.cn （北京大學(xué)）

Chongxiang Huang: chxhuang@scu.edu.cn （四川大學(xué)）

https://doi.org/10.1016/j.scriptamat.2021.114310

 

摘要

了解異質(zhì)結(jié)構(gòu)材料中組成區(qū)域的區(qū)域間相互作用所依賴的機(jī)械行為是基本但具有挑戰(zhàn)性的。在這里，我們報(bào)告了對層壓板中受粗晶粒Cu層約束的納米結(jié)構(gòu)Cu-10Zn層的機(jī)械響應(yīng)的定量研究。納米結(jié)構(gòu)層表現(xiàn)出較大的均勻伸長率，適度的加工硬化，但逐漸降低了工程應(yīng)力。這種獨(dú)特的響應(yīng)主要?dú)w因于層間約束，這導(dǎo)致形成分散的穩(wěn)定應(yīng)變帶，從而使機(jī)械孿晶和堆垛層錯(cuò)廣泛激活。這些發(fā)現(xiàn)為異質(zhì)結(jié)構(gòu)的變形和承載機(jī)制提供了新的見解。

向上滑動(dòng)閱覽英文摘要

Understanding the inter-zone interaction-dependent mechanical behavior of constituent zones in heterostructured material is fundamental but challenging. Here we report quantitative investigations on the mechanical response of a nanostructured Cu-10Zn layer constrained by coarse-grained Cu layers in a laminate. The nanostructure layer displays large uniform elongation, moderate work hardening but gradually reduced engineering stress. Such unique responses are primarily attributed to the inter-layer constraint, which leads to the formation of dispersed stable strain bands and thus enables extensive activation of mechanical twinning and stacking faults. These findings provide new insights into the deformation and load-bearing mechanisms of heterostructures.

 

 

SCRIPTA

Vol. 207, 15 Jan. 2022, 114309

10. Prediction of growth velocity of undercooled multicomponent metallic alloys using a machine learning approach

使用機(jī)器學(xué)習(xí)方法預(yù)測過冷多組分金屬合金的生長速度

 

Vanga Sreekar, Rahul M.R.?, Gandham Phanikumar

Rahul M.R.: rahulmr@iitism.ac.in

https://doi.org/10.1016/j.scriptamat.2021.114309

 

摘要

建立過冷金屬合金的生長動(dòng)力學(xué)對于了解凝固過程中的微觀結(jié)構(gòu)演變至關(guān)重要。迄今為止，物理過程的復(fù)雜性已將增長模型限制為簡單的假設(shè)，這些假設(shè)無法實(shí)現(xiàn)令人滿意的預(yù)測能力。作過冷度函數(shù)的生長速度的實(shí)驗(yàn)測量也很乏味。目前的研究使用實(shí)驗(yàn)和文獻(xiàn)數(shù)據(jù)來訓(xùn)練機(jī)器學(xué)習(xí)算法，訓(xùn)練了五種算法：Random Forest、Bagging Regressor、Gradient Boosting Regressor、XGBoost和Articial Neural Network。使用了910個(gè)標(biāo)記數(shù)據(jù)集，其中70%的數(shù)據(jù)用于訓(xùn)練，30%的數(shù)據(jù)用于測試。ANN的R2交叉驗(yàn)證得分超過0.89。訓(xùn)練后的算法用于預(yù)測中高熵合金的生長速度，與實(shí)驗(yàn)數(shù)據(jù)具有良好的兼容性。

向上滑動(dòng)閱覽英文摘要

Establishing growth kinetics of undercooled metallic alloys is essential to understand microstructure evolution during solidification processing. The complexity of the physical processes have hitherto limited growth models to simple assumptions that do not lead to satisfactory predictive capability. Experimental measurements of growth velocity as a function of undercooling are also tedious. The current study uses experimental and literature data to train the machine learning algorithms. Five algorithms are trained: Random Forest, Bagging Regressor, Gradient Boosting Regressor, XGBoost, and Artificial Neural Network. A labeled data set of 910 was used, with 70% data for training and 30 % data for testing. An R2 cross-validation score of more than 0.89 was obtained for ANN. The trained algorithms are used to predict the growth velocity of medium and high entropy alloys show good compatibility with the experimental data.

 

 

SCRIPTA

Vol. 207, 15 Jan. 2022, 114313

11. Martensitic transformation within nanotwins enhances fatigue damage resistance of a nanotwinned austenitic stainless steel

納米孿晶內(nèi)的馬氏體相變增強(qiáng)了納米孿晶奧氏體不銹鋼的抗疲勞損傷能力

 

Q. Li, D.Y. Liu, F.K. Yan, N.R. Tao?

N.R. Tao: nrtao@imr.ac.cn （中國科學(xué)院金屬研究所）

https://doi.org/10.1016/j.scriptamat.2021.114313

 

摘要

我們研究了一種新型納米孿晶316L不銹鋼的低周疲勞行為，該不銹鋼由嵌入基體中的具有特征位錯(cuò)排列的納米孿晶奧氏體晶粒組成。我們發(fā)現(xiàn)，α\prime-馬氏體轉(zhuǎn)變被激活，橫穿孿晶層，在高應(yīng)變幅度下進(jìn)行納米孿晶晶粒的局部變形。這些α\prime-馬氏體核主要來源于“鋸齒形”滑移帶和孿晶相交處。由于納米孿晶內(nèi)的α\prime-馬氏體相變有效釋放了局部應(yīng)力/應(yīng)變，同時(shí)提高了低周狀態(tài)下的疲勞強(qiáng)度和疲勞壽命。

向上滑動(dòng)閱覽英文摘要

We investigated the low-cycle fatigue behavior of a novel nanotwinned 316L stainless steel consisting of nanotwinned austenitic grains embedded in the matrix with characteristic dislocation arrangements. We excitingly found that the α\prime-martensitic transformation is activated traversing twin lamellae to undertake the localized deformation of nanotwinned grains at high strain amplitudes. These α\prime-martensite nuclei are mainly originated from the intersections between “zigzag” slip bands and twin lamellae. Thanks to the effective release of stress/strain localization by the α\prime-martensitic transformation within nanotwins, the fatigue strength and fatigue life in the low-cycle regime are simultaneously enhanced.

 

 

SCRIPTA

Vol. 207, 15 Jan. 2022, 114319

12. In situ transmission electron microscopy investigation of nucleation of GP zones under natural aging in Al-Zn-Mg alloy

Al-Zn-Mg合金自然時(shí)效下GP區(qū)形核的原位透射電鏡研究

 

Arya Chatterjee?, Liang Qi, Amit Misra

Arya Chatterjee: archatte@umich.edu

https://doi.org/10.1016/j.scriptamat.2021.114319

 

摘要

該研究表明，Al-Zn-Mg合金自然時(shí)效過程中非常早期（一小時(shí)內(nèi)）的析出過程非常復(fù)雜，析出物類型和形成機(jī)制波動(dòng)很大。在透射電子顯微鏡內(nèi)進(jìn)行原位加熱，然后淬火和室溫自然時(shí)效，以研究早期沉淀的形成和演變。研究表明，在非常早期的自然時(shí)效過程中，約2min形成溶質(zhì)簇，隨后在約10min時(shí)與溶質(zhì)簇相鄰的GP-II區(qū)成核。此外，發(fā)現(xiàn)GP-II的成核與GP-I相關(guān)，但不是一種獨(dú)特的機(jī)制。觀察到GP-I沉淀物通過“分離”成核（即從GP-I和Al基質(zhì)之間的界面）或通過原位成核（即從GP-I沉淀物）形成GP-II的位點(diǎn)。有時(shí)可觀察到一些GP-II沉淀物溶解在鋁基體中，而沒有進(jìn)一步轉(zhuǎn)化為?'沉淀物。

向上滑動(dòng)閱覽英文摘要

This investigation reveals very early-stage (within an hour) precipitation during natural-aging of Al-Zn-Mg alloy can have very complex processes with strong fluctuations in precipitate types and formation mechanisms. In situ heating followed by quenching and subsequent natural-aging at room temperature was carried inside transmission electron microscope to study the formation and evolution of early-stage precipitation. Investigation reveals formation of solute clusters at ∼2 mins and subsequent nucleation of GP-II zone adjacent to clusters at ∼10 mins during very early-stage natural-aging. Moreover, nucleation of GP-II is found to be related to GP-I but not in one unique mechanism. GP-I precipitates were observed to act as sites for the formation of GP-II either by ‘separated’ nucleation (i.e. from the interface between GP-I and Al matrix) or via in situ nucleation (i.e. from a GP-I precipitate). Occasionally, some GP-II precipitates were observed to dissolve into Al matrix without further transforming to ?′ precipitates.

 

 

SCRIPTA

Vol. 207, 15 Jan. 2022, 114320

13. Grain boundary segregation and its implications regarding the formation of the grain boundary α phase in the metastable β-Titanium Ti–5Al–5Mo–5V–3Cr alloy

亞穩(wěn)態(tài)β-鈦Ti-5Al-5Mo-5V-3Cr合金中晶界偏析及其對晶界α相形成的影響

 

T.S. Prithiv, Zachary Kloenne, Dian Li, Rongpei Shi, Yufeng Zheng, Hamish L. Fraser, Baptiste Gault, Stoichko Antonov?

Stoichko Antonov: s.antonov@mpie.de

https://doi.org/10.1016/j.scriptamat.2021.114320

 

摘要

我們研究了在β-鈦合金Ti-5Al-5Mo-5V-3Cr-0.5Fe (wt.%)時(shí)效過程中形成的有害晶界α相的起源。采用電子顯微鏡和原子探針探測了淬火狀態(tài)β中小角度和大角度晶界的組成。我們的分析揭示了，一些α相穩(wěn)定元素在兩種類型邊界處的強(qiáng)烈偏析（尤其是氧）以及β相穩(wěn)定元素的消耗。盡管存在這種局部成分偏析，晶界仍保持體心立方結(jié)構(gòu)。我們基于測量的晶界成分的熱力學(xué)計(jì)算表明，偏析顯著增加了時(shí)效時(shí)α成核的化學(xué)驅(qū)動(dòng)力。我們的工作為亞穩(wěn)態(tài)β-Ti合金中沿β晶界形成的非必要晶界α層提供了重要見解，并為這些具有增強(qiáng)機(jī)械性能的合金的微觀結(jié)構(gòu)工程鋪平了道路。

向上滑動(dòng)閱覽英文摘要

We investigated the origin of the deleterious grain boundary α phase formed during the aging of the β-titanium alloy, Ti–5Al–5Mo–5V–3Cr–0.5Fe (wt.%). We probed the composition of low and high-angle grain boundaries from the as-quenched β condition correlating electron microscopy and atom probe tomography. Our analysis reveals strong segregation of some α-stabilizing elements at both types of boundaries, especially oxygen, along with a depletion of β-stabilizing elements. The grain boundary maintains the body-centered-cubic structure despite the presence of this local composition. Our thermodynamic calculations, based on the measured grain boundary compositions, indicate that the segregation significantly increases the chemical driving force for α nucleation upon aging. Our work provides essential insight into the formation of the undesired grain boundary α layers along prior-β grain boundaries in metastable β-Ti alloys and paves the way for microstructural engineering of these alloys with enhanced mechanical properties.