Materials Characterization最新文献

{"title":"Study on phase composition and grain boundary structure of sintered Nd-Fe-Co-B magnet","authors":"Jiateng Zhang ,&nbsp;Mingge Zhou ,&nbsp;Dongli Li ,&nbsp;Fanggui Wang ,&nbsp;Hongsheng Chen ,&nbsp;Yanqiu Xiong ,&nbsp;Jiyuan Xu ,&nbsp;Shengzhi Dong ,&nbsp;Wei Li","doi":"10.1016/j.matchar.2025.115103","DOIUrl":"10.1016/j.matchar.2025.115103","url":null,"abstract":"<div><div>In response to the progressively demanding operational conditions imposed on permanent magnet materials, the advancement of sintered Nd-Fe-Co-B permanent magnets exhibiting high temperature stability holds great importance. The magnetic properties and temperature stability of sintered Nd-Fe-Co-B magnets have been widely recognized. However, their internal structure is complex and has phases that reduce coercivity. There is still little research on their phase composition and microstructure. This study involved the fabrication of magnet powder with Co contents of 0.5 wt% and 16 wt%, which were subsequently employed in the production of magnets through the application of powder metallurgy techniques. Both the magnet powder and the magnets were characterized, and it was found that the RE(Fe,Co)₂ phase and RE₂(Fe,Co)₁₇ phase already existed in the magnet powder. The phenomenon of Co element migrating from grain boundaries to the 2–14-1 phase was discovered. In addition, crystalline Co-rich thin-layer grain boundary phases were also discovered in the magnets. Ultimately, this study provides a reference for understanding the phase transition and properties in sintered Nd-Fe-Co-B magnets.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"225 ","pages":"Article 115103"},"PeriodicalIF":4.8,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143911991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The ablation behavior and mechanism of nanosecond laser machined SiCf/SiC composite under different assisted gases","authors":"Yue Cao ,&nbsp;Bin Wang ,&nbsp;Zhehang Li ,&nbsp;Jiajia Wang ,&nbsp;Shanshan Chen ,&nbsp;Kailiang Mao ,&nbsp;Qunli Zhang ,&nbsp;Wenwu Zhang ,&nbsp;Liyuan Sheng","doi":"10.1016/j.matchar.2025.115096","DOIUrl":"10.1016/j.matchar.2025.115096","url":null,"abstract":"<div><div>As a kind of emerging ceramic matrix composites (CMCs), the SiC_f/SiC composite has demonstrated many advantages in the aerospace industry. However, its ultrahigh hardness and local brittleness greatly increase the machining difficulty by conventional methods. In the present research, the nanosecond laser had been employed to machine the SiC_f/SiC composite with different gases (O₂, N₂, and He), single pulse energy, and gas pressure. The laser machined SiC_f/SiC composite surfaces were characterized to reveal the influence of parameters on ablation behavior. The results exhibit that the gas type and single pulse energy influence the ablation of SiC_f/SiC composite significantly. Specifically, the laser ablation efficiency in O₂ gas is relative higher, but the oxidation is evident and the spattering is large. In contrast, the N₂ and He gases decrease the ablation efficiency and spattering, but the oxidation is also eliminated mostly as well. With the increasing of single pulse energy, the laser ablation efficiency, heat-affected zone and spattering enhanced simultaneously. Comparatively, the increased the gas pressure increases the laser ablation efficiency and spattering a little. Except for the slag taken away by gas stream, the active gas realizes the high-efficiency ablation by assisting reaction and vaporization, while the inert gas mainly depends on vaporization. In general, the high-power laser combining with high-pressure O₂ gas might be more appropriate for rough machining of SiC_f/SiC composite, which ensures the ablation efficiency. While the low-power laser with high-pressure inert atmosphere would be the best choice for final machining of SiC_f/SiC composite, which ensures the ablation quality. Such research might give a light on the machining of CMCs by nanosecond laser.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"225 ","pages":"Article 115096"},"PeriodicalIF":4.8,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143899407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Weak penetration strategy combined with post-weld aging treatment to optimize interface joining for dissimilar friction stir lap welded aluminum and titanium alloys","authors":"Han Li ,&nbsp;Huijie Zhang ,&nbsp;Xu Liu ,&nbsp;Rui Sun ,&nbsp;Qiuzhi Gao ,&nbsp;Kang Ma ,&nbsp;Jianling Song ,&nbsp;Yunqiang Zhao","doi":"10.1016/j.matchar.2025.115097","DOIUrl":"10.1016/j.matchar.2025.115097","url":null,"abstract":"<div><div>In order to address the problems caused by excessive tool penetration into lower hard sheet during the friction stir lap welding (FSLW) of aluminum and titanium alloys, a weak penetration strategy combined with a post-weld low-temperature aging treatment is proposed and investigated for the dissimilar FSLW of 6061-O aluminum alloy and Ti-6Al-4V titanium alloy in the present research. The results indicate that post-weld aging is capable of the elimination of cracks and voids formed at the hook structure during Al/Ti FSLW at relatively low rotation speed. Additionally, the low-temperature aging renders an improvement in bonding strength of lap surface, leading to the maximum joint efficiency of 95.5 % relative to the Al matrix. Microstructural analyses on weld interface reveal that the further recrystallization caused by aging induces approximately 90° rotation and obvious refinement for the stir zone grains. Furthermore, the smoother and more flattened Al/Ti weld interface characterized by a significant reduction in fragments and intermetallic compound clusters is produced through Gibbs-Thomson effect and Ostwald ripening principle during post-weld aging. The both factors represent the core mechanism through which low-temperature aging optimizes the interface structure and improves the joint performance. This research provides an effective technological approach for the interface optimization of Al/Ti lap joint, achieving a controllable balance between weld formation and mechanical property for significant practical implications.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"224 ","pages":"Article 115097"},"PeriodicalIF":4.8,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143891873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanical properties of the GS24Mn4 steel - Inconel 718 interface manufactured by laser metal deposition and compound casting","authors":"Brian Zhan Rui Lee ,&nbsp;Lewei He ,&nbsp;Soon Siang Chong ,&nbsp;Hua Li","doi":"10.1016/j.matchar.2025.115102","DOIUrl":"10.1016/j.matchar.2025.115102","url":null,"abstract":"<div><div>This work investigates the joining phenomena between GS24Mn4 steel (WCB) and Inconel 718 (IN718) manufactured by additive manufacturing and compound casting. Modified heat treatment techniques namely annealing followed by quick aging (SAA) and annealing followed by direct aging (ADA) are studied regarding their effects on the interfacial hardness and tensile strength, followed by a thorough characterization of the interface microstructure and fracture surface. It is found that both techniques meet the micro hardness specification while ADA specimens perform better in terms of their strength. Moreover, the mass dendrite porosities on the fracture surface originating from compound casting shrinkage is the main cause of premature failure. It is also observed that wide and coarse grains of IN718 at the interface causes a shift in the location of material fracture from the weaker WCB to IN718 alloy.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"225 ","pages":"Article 115102"},"PeriodicalIF":4.8,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143899408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phase hardness, load transfer, texture, and martensitic transformation induced dynamic grain refinement sources of hardening in three structurally transforming high entropy alloys","authors":"Utku Uzun ,&nbsp;Nicholas Pitkin ,&nbsp;Marko Knezevic","doi":"10.1016/j.matchar.2025.115093","DOIUrl":"10.1016/j.matchar.2025.115093","url":null,"abstract":"<div><div>This paper describes the findings from an experimental investigation into local and overall strength of three microstructurally flexible high entropy alloys (HEAs), Fe₄₂Mn₂₈Co₁₀Cr₁₅Si₅ (Si-HEA), Fe_38.5Mn₂₀Co₂₀Cr₁₅Si₅Cu_1.5 (Cu-HEA) and Fe_37.5Mn₂₀Co₂₀Cr₁₅Si₅Cu_1.5V₁ (V-HEA) in at.%. The alloys are similar in composition and consist of metastable face-centered cubic austenite (γ) and stable hexagonal epsilon martensite (ε) phases. The Si-HEA also contains stable tetragonal sigma (σ) phase. The contents of diffusion-created phase, σ, remains constant during plastic deformation, while the fraction of diffusion less strain-induced γ → ε phase transformation increases. The evolution of phases, as well as the local and overall strength, during deformation of the alloys were characterized. High throughput nanoindentation mapping was employed to assess the mechanical hardness of individual phases with plastic strain. The γ and ε phases were found to exhibit moderate hardening with plasticity owing to dislocations, while the σ phase softened owing to the phase fragmentation. The primary source of the overall strain hardening in the alloys was found to be dynamic refinement of the structures and underlying barrier effect, while the increasing fraction of the dislocated ε phase and texture were found to act as secondary sources of hardening. The load transfer strengthening was found significant only in the Si-HEA because of the presence of the strong and brittle σ phase. The measured hardness per phase, load transfer, texture, and martensitic transformation induced dynamic grain refinement hardening mechanisms were assessed to explain similarities and differences in the hardening behavior of the three structurally transforming HEAs.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"224 ","pages":"Article 115093"},"PeriodicalIF":4.8,"publicationDate":"2025-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143887264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of the grain size, boundary type and texture on the bending properties of phosphorus bronze strips","authors":"Zhongping Chen ,&nbsp;Yang Yang ,&nbsp;Huafen Lou ,&nbsp;Hu Wang ,&nbsp;Chaojian Xiang","doi":"10.1016/j.matchar.2025.115090","DOIUrl":"10.1016/j.matchar.2025.115090","url":null,"abstract":"<div><div>The bending formability of phosphorus bronze strips plays a critical role in determining the service performance of board-to-board connectors. The mechanisms of grain size, boundary type, and texture influences on bending property of phosphorus bronze was systematically investigated in this work. The results demonstrate that the bending properties of phosphorus bronze strips was improved with reduced grain size, and excellent bending formability can be achieved when the grain size was controlled below 2 μm. Grain boundary engineering, which increases the fraction of special boundaries, effectively mitigates internal stress concentration within grains, thereby improving the bending properties of phosphorus bronze strips. However, as rolling reduction increases, deformation textures such as Brass, Goss, and rotated-Goss significantly strengthen. Notably, the continuous evolution of the Brass texture can induce shear band formation in the alloy, which adversely affects the bending properties along the bad way. Synergistic control of fine grain, boundary type, and cold deformation is essential for achieving high tensile strength and superior bending formability of phosphorus bronze strips. This research offers valuable insights into the development of advanced connector materials</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"225 ","pages":"Article 115090"},"PeriodicalIF":4.8,"publicationDate":"2025-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143899561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultrasonic-assisted rapid fabrication of Cu foam/Cu-Sn IMC composite interlayers for high-temperature die-attach applications","authors":"L. Zhu,&nbsp;J. Ren,&nbsp;M.L. Huang","doi":"10.1016/j.matchar.2025.115100","DOIUrl":"10.1016/j.matchar.2025.115100","url":null,"abstract":"<div><div>The development of full intermetallic compound (IMC) joints with high melting temperatures is critical for advanced die-attach in third-generation semiconductor power devices. This study demonstrates an innovative ultrasonic-assisted manufacturing strategy to fabricate high-performance Cu foam/Cu-Sn IMC composite interlayers, consisting of three-dimensional continuous Cu foam skeletons, Cu₆Sn₅ and Cu₃Sn IMCs, by low-power ultrasonic-assisted immersion soldering (260 °C, 180 s). The rapid fabrication of composite interlayer was attributed to that the cavitation erosion effect promoted the wettability of the molten Sn on Cu surface, and the acoustic cavitation and streaming effects simultaneously enhanced both the dissolution rate and the diffusivity of substantial Cu atoms from high specific surface area Cu foam into the molten Sn. The composite joints prepared by diffusion bonding of two Cu substrates with the composite interlayers achieved the metallurgical bonding through the formation of thin interfacial Cu₃Sn IMCs. The optimized composite joint demonstrated exceptional mechanical performance with a shear strength of 65.3 MPa and fracture elongation of 33.1 %, owing to the combined effects of the fine grain strengthening of Cu-Sn IMCs induced by the ultrasonic vibration and the ductile three-dimensional continuous Cu foam skeletons.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"224 ","pages":"Article 115100"},"PeriodicalIF":4.8,"publicationDate":"2025-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143887267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deep learning accelerated micrograph-based porosity defect quantification in additively manufactured steels for uncovering a generic process-defect-properties relation","authors":"Jingxuan Zhao ,&nbsp;Chunguang Shen ,&nbsp;Minghao Huang ,&nbsp;Yu Qi ,&nbsp;Yusheng Chai ,&nbsp;Shijian Zheng","doi":"10.1016/j.matchar.2025.115094","DOIUrl":"10.1016/j.matchar.2025.115094","url":null,"abstract":"<div><div>To date, the micrograph-based defect examination remains one of the primary methods for evaluating the quality of additively manufactured (AM) components due to its low cost and unique advantage in providing direct and precise observations of existing defects. However, traditional micrograph-based defect examination typically relies on human operation, which largely restricts its efficiency and repeatability owing to subjective manual intervention, thereby impeding the accurate and rapid evaluation of defects in large-scale specimens. In this study, deep learning (DL) is employed to accelerate the micrograph-based defect examination via training a semantic segmentation model for defect recognition and quantification, contributing to enhance both the efficiency and precision of this method by replacing conventional manual operations. The proposed DL method is successfully applied to 50 laser powder bed fusion (L-PBF) specimens of 18Ni300 maraging steel to rapidly and accurately recognize two kinds of porosity defects, i.e., Gas-Entrapped Pore (GEP) and Lack of Fusion (LoF), in 5000 micrographs and then provide reliable quantification outcomes. Furthermore, a generic relation among printed parameters, porosity information, and tensile properties is meticulously investigated based on these large-scale quantitative defect results. Besides, this work also provides a detailed discussion of the trained model's robustness to image quality and sample quality, as well as the impact of the observation area on the quantification results.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"225 ","pages":"Article 115094"},"PeriodicalIF":4.8,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143899409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tuning recrystallization texture via two-step pre-recovery for cold rolled pure tantalum sheet","authors":"Ye Tang,&nbsp;Yu Peng,&nbsp;Dunqiang Tan","doi":"10.1016/j.matchar.2025.115091","DOIUrl":"10.1016/j.matchar.2025.115091","url":null,"abstract":"<div><div>Two-step pre-recovery processes followed by recrystallization annealing were designed to regulate the recrystallization textures for the pure tantalum sheet. The results show that the directly recrystallized microstructure has a strong γ fiber. The fraction of α fiber comparable to that of γ fiber in the recrystallized microstructures with fine grains and a higher recrystallized fraction can be achieved by the two-step pre-recovery at lower or higher temperatures for relatively short time followed by recrystallization annealing. The fraction of γ fiber increases in the recrystallized microstructures after pre-recovery at lower temperatures for shorter or intermediate time or at intermediate temperatures, due to the retarded recrystallization of the α-oriented grains and thus the distinct advantage in the evolution of recrystallized grains for the γ-oriented grains. The two-step pre-recovery at lower temperatures for much longer time also leads to an obviously increased fraction of γ fiber in the recrystallized microstructure, which is closely related to the size advantage of the γ-oriented recrystallized grains.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"224 ","pages":"Article 115091"},"PeriodicalIF":4.8,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143887266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of infiltration matrix types on ablation resistance of C/C-SiC-ZrC-Cu composites by low-temperature reactive melt infiltration","authors":"Longquan Huang ,&nbsp;Jian Yin ,&nbsp;Shuai Wang ,&nbsp;Xiang Xiong ,&nbsp;Hongbo Zhang ,&nbsp;Jinglv Zuo","doi":"10.1016/j.matchar.2025.115084","DOIUrl":"10.1016/j.matchar.2025.115084","url":null,"abstract":"<div><div>Ultra-high temperature ceramics modified carbon/carbon composites, crucial for aerospace throats, require enhanced ablation resistance in extreme environments. Inspiring by the active cooling properties of Cu in thermal protection systems, C/C-SiC-ZrC-Cu composites were prepared by two-step low-temperature reactive melt infiltration using Zr<img>Cu infiltration material. The effects of the different Zr<img>Cu materials on the microstructure and ablation resistance of the C/C-SiC-ZrC-Cu composites were investigated. The C/C-SiC-ZrC-Cu composites exhibited a uniform composition and stable structure, with an open porosity of about 5 % and a density of about 2.80 g/cm³. During the plasma ablation testing, the modified composites exhibited mass and linear ablation rates of 4.50 mg/s and − 1.50 μm/s after 20 s and 5.25 mg/s and 0.88 μm/s after 40 s, respectively. The substantial enhancement in short-term ablation resistance of the composites can be attributed to the synergistic effects of the ablation resistance and self-healing capabilities of the SiO₂-ZrO₂ layer, coupled with the active cooling effect of Cu evaporation.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"224 ","pages":"Article 115084"},"PeriodicalIF":4.8,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143881350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}