Materials Characterization最新文献

{"title":"Differential micrograph imaging for visualization of strain localization","authors":"Connor J. Lopez ,&nbsp;Brady G. Butler ,&nbsp;Kelvin Y. Xie","doi":"10.1016/j.matchar.2025.115626","DOIUrl":"10.1016/j.matchar.2025.115626","url":null,"abstract":"<div><div>In this work, we introduce differential micrograph imaging (DMI), a technique developed to reveal subtle microstructural changes associated with strain localization in polished and etched metallic samples subjected to mechanical loading. The method first applies image registration to suppress rigid body motion and global deformation. A pixel-wise subtraction from the undeformed reference micrograph then isolates contrast variations arising from localized strain. DMI does not require speckle patterning and leverages information from every pixel in the micrograph. In contrast, digital image correlation (DIC) relies on surface patterning, and its spatial resolution is fundamentally limited by the subset and speckle size. While DMI is a semi-quantitative technique where heat map intensity correlates with relative strain magnitude, it does not provide exact strain values or directions. Nonetheless, DMI can serve as a complementary technique to DIC by enabling high-resolution visualization of localized microstructural changes, particularly in regions with complex features and subtle deformation-induced microstructure changes.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"229 ","pages":"Article 115626"},"PeriodicalIF":5.5,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145265563","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":"Microstructure evolution and Interface morphology optimization in synergistic double-sided probeless friction stir spot welding of dissimilar 7075/6061 aluminum alloys","authors":"Wenlong Fan ,&nbsp;Haiyu Xu ,&nbsp;Xiawei Yang ,&nbsp;Yu Su ,&nbsp;Wenya Li ,&nbsp;Shitong Ma ,&nbsp;Zhenguo Guo ,&nbsp;Qiang Chu ,&nbsp;Tiejun Ma","doi":"10.1016/j.matchar.2025.115598","DOIUrl":"10.1016/j.matchar.2025.115598","url":null,"abstract":"<div><div>This study introduces Synergistic Double-Sided Probeless Friction Stir Spot Welding (SDP-FSSW) as a novel solid-state technique for joining dissimilar aluminum alloys, specifically AA7075-T8 and AA6061-T4, which differ markedly in their mechanical properties. The primary objective was to systematically investigate how varying the rotational speeds of the upper and lower tool shoulders affects weld formation, microstructural evolution, and joint mechanical performance. By independently controlling the rotation speeds of both tool shoulders, the process enabled precise regulation of interfacial morphology, heat input, and plastic flow, resulting in flat, defect-free welds with controlled hook formation and significant material intermixing. Tensile-shear tests showed that all joints exhibited strengths above 5 kN. Under optimal conditions—600/200 rpm with a dwelling time of just 3 s—the joint achieved a maximum tensile-shear strength of 9585.9 N. These results demonstrate that SDP-FSSW provides superior control over interface morphology and joint properties, offering significant potential for fabricating high-strength, lightweight, multi-material structures in advanced manufacturing.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"229 ","pages":"Article 115598"},"PeriodicalIF":5.5,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145265557","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":"Directed energy deposition of aluminium bronze onto H13 steel-microstructure in multi-material additive manufacturing","authors":"H.E.S. Linga ,&nbsp;C. Hatzoglou ,&nbsp;Y. Zhang ,&nbsp;V. Brøtan ,&nbsp;I. Westermann ,&nbsp;X. Ren ,&nbsp;B. Holmedal","doi":"10.1016/j.matchar.2025.115603","DOIUrl":"10.1016/j.matchar.2025.115603","url":null,"abstract":"<div><div>Multi-material additive manufacturing has over the years had increasing interest due to the possibility of combining attributes of different alloys to create parts with tailored properties. This study investigates the combination of aluminium bronze and AISI H13 tool steel, through laser-based directed energy deposition with powder feedstock and focuses on the microstructure near the bonding interface. Combining such materials can utilize the thermal properties of bronze and the mechanical properties of tool steel. The characterization was performed using a variety of techniques, including optical– and secondary electron microscopy, atom probe tomography, and X-ray microtomography. The deposition of bronze onto steel resulted in an interface nearly free of imperfections between steel and bronze, as well as a mixing zone where nearly spherical iron-rich particles were suspended in a bronze matrix. The miscibility gap in the iron-copper liquid primarily caused the formation of these spherical iron-rich particles, and the separation of elements in the liquid phase is believed to prevent the formation of intermetallic particles. Additionally, the region around the mixing zone exhibited increased hardness, approximately 1 mm above and below the bronze-steel interface, compared to the bulk bronze and steel.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"229 ","pages":"Article 115603"},"PeriodicalIF":5.5,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145265560","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":"Abnormal grain growth in friction stir–processed Al–Mg–Zn–Sc alloys","authors":"J.C. Xie,&nbsp;C.Y. Liu,&nbsp;Q.J. Li,&nbsp;Y.L. Sun","doi":"10.1016/j.matchar.2025.115624","DOIUrl":"10.1016/j.matchar.2025.115624","url":null,"abstract":"<div><div>This study investigates the grain coarsening behavior of fine-grained Al–7 Mg–xZn–0.25Sc alloys manufactured by friction stir processing (FSP) during solid solution treatment. The FSP alloys containing Zn ≤3 wt% demonstrated excellent thermal stability of their grain structure during heating. However, when the Zn content increased to 5 wt%, abnormal grain growth (AGG) was observed in both the top and bottom regions of the low-heat-input FSP alloy after 88 s of heat treatment, followed by rapid propagation of coarse grains toward the central region within the next 100 s. The grain structure showed stabilization tendencies after 180 s of thermal exposure. While, increasing heat input can delay grain coarsening, or even completely inhibit AGG in the FSP Al–7 Mg–5Zn–0.25Sc alloy during heat treatment. The AGG phenomenon in the top and bottom regions can be attributed to the initial grain size was significantly smaller than the critical grain size (∼1.8 μm) required to inhibit grain boundary migration, as predicted by the Humphreys model‌. ‌Grain growth is also governed by the size and dissolution kinetics of secondary <em>T</em> phases within the alloy system.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"229 ","pages":"Article 115624"},"PeriodicalIF":5.5,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145265554","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":"Through-thickness microstructure and residual stress distributions in additive friction stir deposited Aluminum 7075","authors":"Peter C. Metz ,&nbsp;Lauren Miller ,&nbsp;Joshua Kincaid ,&nbsp;Elijah Charles ,&nbsp;Andrew T. Wood ,&nbsp;Zachary C. Sims ,&nbsp;Sean Drewry ,&nbsp;Austin Houston ,&nbsp;Jeffrey R. Bunn ,&nbsp;Brett Compton ,&nbsp;Tony Schmitz ,&nbsp;Eric A. Lass ,&nbsp;Dayakar Penumadu ,&nbsp;Katharine Page","doi":"10.1016/j.matchar.2025.115600","DOIUrl":"10.1016/j.matchar.2025.115600","url":null,"abstract":"<div><div>Aluminum 7075-T651 was printed by additive friction stir deposition (AFSD) onto 7075-T651 substrate with one-directional passes to form a <span><math><mo>∼</mo></math></span>190 mm wall <span><math><mo>∼</mo></math></span>27 mm in height. Neutron residual stress mapping of the as-printed sample was performed in the longitudinal (LD), transverse (TD), and normal (ND) directions of the build at the longitudinal midplane of the wall with 6 mm LD x 3 mm TD x 3 mm ND voxels. These data were contextualized with microhardness and plastometry mapping, powder X-ray diffraction, electron backscatter diffraction, and scanning transmission electron microscopy. Peak tensile stresses were observed in the base plate 4–5 mm below the base plate-AFSD interface with maximum values of 168 ± 20 MPa LD, 152 ± 16 MPa TD, and 129 ± 16 MPa ND. Peak compressive stresses were located in the deposit, with maximum values −63 ± 19 MPa LD, −39 ± 16 MPa TD, and −67 ± 16 MPa. Gaussian process regression was used to estimate the strength and residual stress values at congruent points throughout the analysis plane. The region of peak residual tensile stress was found to reach 32% of the von Mises yield criterion. The spatial distribution of hardness and strength in the part was found to be independent of grain size effects (<span><math><msub><mrow><mi>d</mi></mrow><mrow><mn>50</mn></mrow></msub></math></span> <span><math><mo>∼</mo></math></span> <span><math><mrow><mn>1</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span>) but to correlate with the spatial distribution of work hardening, solution strengthening, and precipitation strengthening, reaching an apparent steady state 15 mm below the final AFSD surface.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"229 ","pages":"Article 115600"},"PeriodicalIF":5.5,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145265555","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":"Microstructure, mechanical property, and corrosion behavior of hybrid SLM-LMD additively manufactured 17–4pH stainless steel","authors":"Miao Sun ,&nbsp;Wenhua Guo ,&nbsp;Jianxun Zhang ,&nbsp;Bingheng Lu","doi":"10.1016/j.matchar.2025.115611","DOIUrl":"10.1016/j.matchar.2025.115611","url":null,"abstract":"<div><div>This study systematically investigates the microstructure, mechanical properties, and corrosion resistance of 17–4pH stainless steel fabricated by hybrid additive manufacturing (AM) processes. This hybrid approach aims to overcome the limitations of single process AM in producing or repairing large parts by combining the high precision and fine microstructure of SLM with the high deposition efficiency of LMD. Samples produced by hybrid AM were compared with those from single SLM or LMD processes through microstructural characterization (SEM, EBSD), mechanical testing (microhardness, tensile), and electrochemical measurements. Key findings include: (1) Hybrid-processed 17–4pH exhibits stable composition without fluctuations at the SLM-LMD interface. The high heat input of LMD in the hybrid process significantly changes the content of γ - austenite in the SLM matrix (e.g., 16.1 % on the SLM side of LMD-SLM, while the content in the single process SLM-HT sample was 2.38 %). (2) Mechanically, SLM heat-treated samples showed peak hardness (340 HV_0.5), while as-deposited SLM exhibited the lowest (220 HV_0.5). Hybrid samples displayed hardness variations &lt;50 HV_0.5 across regions and an ∼800 μm wide heat-affected zone. Tensile tests revealed anisotropy: In the XOY plane, LMD-SLM achieved 1030 MPa (UTS) / 26.41 % (elongation) vs. SLM-LMD's 966 MPa / 27.16 %; in the YOZ plane, both hybrid samples exceeded 1000 MPa UTS and 60 % elongation without interface fracture. (3) Regarding corrosion resistance, as-deposited SLM samples performed best, followed by as-deposited LMD. The corrosion resistance of SLM samples significantly decreases after heat treatment. SLM-LMD hybrid sample exhibited corrosion resistance comparable to the SLM heat-treated one. These results confirm the feasibility of the SLM-LMD hybrid process for high-performance repair/remaufacturing of 17–4pH components, providing valuable insights into the microstructure-property relationships critical for aerospace and energy applications.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"229 ","pages":"Article 115611"},"PeriodicalIF":5.5,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145265048","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":"In-situ grown graphene enhanced oxidation resistance of NiAl","authors":"Jiayi Peng,&nbsp;Zeqian Wu,&nbsp;Zihang Li,&nbsp;Zi Wang,&nbsp;Liming Tan,&nbsp;Yan Wang,&nbsp;Lan Huang,&nbsp;Feng Liu","doi":"10.1016/j.matchar.2025.115610","DOIUrl":"10.1016/j.matchar.2025.115610","url":null,"abstract":"<div><div>Graphene was in-situ synthesized during hot-pressed sintering process by mixing NiAl with glucose, and the effect of graphene on high-temperature oxidation performance was investigated. During oxidation, the oxide scale on NiAl spalled after 50 h of exposure and led to the exposure of the underlying metal to further oxidation. In contrast, the oxidation kinetics of NiAl-Gr followed a parabolic law and stabilized after 75 h. The presence of graphene played a crucial role in these observations. Graphene facilitated the transformation of transient Al₂O₃ phases into stable α-Al₂O₃, which resulted in a uniform and continuous oxide scale. Moreover, graphene bridged the interface between the matrix and the oxide scale, thereby improving the adhesion of the oxide scale. Graphene also reduced the residual stress within the oxide scale by refining the α-Al₂O₃ grains. The stress reduction suppressed spallation and consequently improved the high-temperature oxidation resistance of NiAl.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"229 ","pages":"Article 115610"},"PeriodicalIF":5.5,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145227040","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":"Improving the high-temperature tensile properties of titanium alloys by elemental enrichment at grain boundaries","authors":"Xuefeng Ding ,&nbsp;Shunzhang Yuan ,&nbsp;Binquan Jin ,&nbsp;Xuefeng Zhang ,&nbsp;Liang Yang ,&nbsp;Lizhong Zhao ,&nbsp;Yuqiang Chen ,&nbsp;Minbo Wang ,&nbsp;Yang Liu ,&nbsp;Yufeng Song","doi":"10.1016/j.matchar.2025.115609","DOIUrl":"10.1016/j.matchar.2025.115609","url":null,"abstract":"<div><div>Titanium alloys are widely used in aerospace applications due to their excellent heat resistance and high specific strength. However, their high-temperature strength enhancement is constrained by grain boundary slip phenomena at elevated temperatures. In this study, a TA0-(9 wt%) NiAlCrMoZr titanium alloy was fabricated via laser-directed energy deposition (LDED) to systematically investigate the formation mechanism of interfacial element enrichment and its influence on high-temperature tensile properties. Owing to the different diffusion rates of elements in β-Ti, Ni and Mo were enriched at the grain boundary of α phase and β phase interfaces by tailoring the heat treatment temperature. Notably, the specimen heat-treated at 900 °C demonstrated a 9.0 % enhancement in high-temperature tensile strength and an 88.6 % improvement in elongation at 600 °C compared to its counterpart treated at 800 °C. These significant improvements in high-temperature mechanical properties are primarily attributed to interfacial element enrichment. On one hand, the strengthening effect by grain boundary element enrichment on grain boundaries is greater than the weakening effect caused by grain boundary coarsening, thereby increasing the high-temperature strength. On the other hand, the strengthening of grain boundaries by element enrichment promotes the synergistic deformation of grain boundaries and grain interiors, significantly increasing the elongation of the alloy. Furthermore, the interfacial enrichment of Ni and Mo is ascribed to the epitaxial growth of the α phase during high-temperature processing and the mismatch in atomic diffusion rates during rapid cooling. This work may provide valuable insights into microstructure design strategies for optimizing the high-temperature performance of titanium alloys.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"229 ","pages":"Article 115609"},"PeriodicalIF":5.5,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145265047","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":"Effect of indium (In) on the microstructure evolution, grain orientation and mechanical behaviors of Sn58Bi/Cu solder joints under thermal cycling","authors":"Wenhao Wang ,&nbsp;Lei Sun ,&nbsp;Peng He ,&nbsp;Liang Zhang ,&nbsp;Jing Li ,&nbsp;Shuye Zhang","doi":"10.1016/j.matchar.2025.115608","DOIUrl":"10.1016/j.matchar.2025.115608","url":null,"abstract":"<div><div>The effects of adding 0.3 wt% submicron-sized indium (In) particles on the microstructure evolution, grain orientation, and mechanical behaviors of the Sn58Bi solder joints under thermal cycling were systematically characterized. The results reveal that In particles can promote microstructure refinement of Sn58Bi/Cu solder joint and suppress the coarsening and segregation of the Bi phase. At the Sn58Bi/Cu interface, In promoted the rapid formation of the Cu₆(Sn,In)₅ IMC layer, but inhibited the growth of the brittle Cu₃Sn layer. After 1200 thermal cycles, the thickness of IMC layer of the Sn58Bi/Cu and Sn58Bi-0.3In/Cu solder joints was 3.964 μm and 4.781 μm, respectively. Moreover, the IMC grains of Sn58Bi-0.3In/Cu solder joint were larger than those of the Sn58Bi/Cu solder joint under thermal cycling. Through EBSD analysis, the addition of In particles improved the grain orientation consistency of the microstructure of Sn58Bi/Cu, achieving directional regulation of the interfacial IMC. In addition, the shear strength and microhardness of Sn58Bi/Cu solder joints were enhanced with In particles, maintaining a 9.6 % higher shear strength and 16.7 % higher microhardness than unmodified Sn58Bi under 1200 thermal cycles.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"229 ","pages":"Article 115608"},"PeriodicalIF":5.5,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145265561","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":"Effect of defocus distance and energy density on melt pool morphology, surface roughness, and grain orientation of 70/30 copper-nickel alloy in laser powder bed fusion","authors":"Mahdi Nadimi ,&nbsp;Lucy Waite ,&nbsp;Jie Song ,&nbsp;Yao Fu","doi":"10.1016/j.matchar.2025.115605","DOIUrl":"10.1016/j.matchar.2025.115605","url":null,"abstract":"<div><div>This study examined the impact of defocus distance (D) and volumetric energy density (E_v) on the melt pool morphology, surface properties, and microstructure of a pre-alloyed 70/30 copper‑nickel fabricated using laser powder bed fusion (LPBF). Samples were created with defocus distances ranging from −20 mm to 20 mm and energy densities between 125.0 and 381.0 J/mm³. Analysis methods included optical microscopy, surface topography, and electron backscatter diffraction. A defocus distance of −10 mm combined with moderate energy density (125.0–222.2 J/mm³) yielded deep V-shaped melt pools, low surface roughness (Ra = 23.6 μm), well-aligned crystallographic textures with a Multiple of Uniform Density (MUD) of 6.59. Positive defocus (D = 20 mm) with high energy density produced shallow, disk-like melt pools with acceptable roughness, favoring (001) crystallographic texture. Although deep V-shaped melt pools enable enhanced penetration, they are more susceptible to defects caused by keyhole formation. Conversely, shallow disk-shaped conduction mode melt pools offer better stability and fewer surface irregularities, but they may suffer from insufficient penetration and other drawbacks. These findings highlight the potential of using defocus parameter as a key design parameter to optimize melt pool characteristics for specific material and process requirements in LPBF.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"229 ","pages":"Article 115605"},"PeriodicalIF":5.5,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145265565","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}