Pub Date : 2022-03-25DOI: 10.1080/00325899.2022.2055888
Simon Gélinas, C. Blais
ABSTRACT Liquid phase sintering (LPS) of powder metallurgy (PM) components is a well-recognised strategy to enhance the densification of pressed-and-sintered compacts. This work reports the investigation on the liquid phase formation when a Fe–Ni–Mn–C–B master alloy (MA) is used as a boron carrier in combination with two iron base powders pre-alloyed with Mo. Through differential scanning calorimetry tests, quantitation of the microstructure with the help of artificial intelligence, as well as measurement of sintered density and strength as a function of sintering temperature, it was possible to unravel the mechanisms that take place before and during LPS. It was confirmed that a cascade of events takes place in the solid state prior to reaching the temperature necessary for a eutectic reaction to form a liquid. Additionally, the pre-alloyed Mo content was identified as a factor that modifies the initiation of LPS but not the LPS mechanisms per se.
{"title":"Characterisation of the mechanisms taking place during liquid phase sintering of PM boron steels with the help of artificial intelligence","authors":"Simon Gélinas, C. Blais","doi":"10.1080/00325899.2022.2055888","DOIUrl":"https://doi.org/10.1080/00325899.2022.2055888","url":null,"abstract":"ABSTRACT Liquid phase sintering (LPS) of powder metallurgy (PM) components is a well-recognised strategy to enhance the densification of pressed-and-sintered compacts. This work reports the investigation on the liquid phase formation when a Fe–Ni–Mn–C–B master alloy (MA) is used as a boron carrier in combination with two iron base powders pre-alloyed with Mo. Through differential scanning calorimetry tests, quantitation of the microstructure with the help of artificial intelligence, as well as measurement of sintered density and strength as a function of sintering temperature, it was possible to unravel the mechanisms that take place before and during LPS. It was confirmed that a cascade of events takes place in the solid state prior to reaching the temperature necessary for a eutectic reaction to form a liquid. Additionally, the pre-alloyed Mo content was identified as a factor that modifies the initiation of LPS but not the LPS mechanisms per se.","PeriodicalId":20392,"journal":{"name":"Powder Metallurgy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45063683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-23DOI: 10.1080/00325899.2021.2023414
Marco Mitterlehner, H. Danninger, C. Gierl-Mayer, J. Frank, W. Tomischko, Harald Gschiel
ABSTRACT Currently there is considerable interest in understanding and quantifying the powder characteristics that affect the quality of the top spread powder layer for processes such as powder bed fusion and binder jetting. For this purpose, a new testing device has been developed in order to assess several aspects of this top spread powder layer. Using different measurement procedures, the roughness of the top layer, the surface coverage of a single spread powder layer and the powder bed density of an entire spreading experiment can be determined. Since the tester is freely programmable, the individual process steps of spreading a single powder layer can also be varied. Using these methods, the influence of different process parameters such as e.g. the spreading velocity or the distance between the blade and the building platform, which is also referred to as gap size in general, on the quality of the top or only a single spread layer and on the powder bed packing density can be examined. This study presents the new test device as well as the corresponding measurement procedures mentioned, the reproducibility of the results, which, depending on the measurement method and the measured parameter, range between 0.24 and 4.81%, and the influence of the spreading strategy, which defines the chronological order of the single steps during spreading.
{"title":"Novel testing device and routine to characterise the spreadability of powders for powder bed fusion processes – a problem-oriented approach","authors":"Marco Mitterlehner, H. Danninger, C. Gierl-Mayer, J. Frank, W. Tomischko, Harald Gschiel","doi":"10.1080/00325899.2021.2023414","DOIUrl":"https://doi.org/10.1080/00325899.2021.2023414","url":null,"abstract":"ABSTRACT Currently there is considerable interest in understanding and quantifying the powder characteristics that affect the quality of the top spread powder layer for processes such as powder bed fusion and binder jetting. For this purpose, a new testing device has been developed in order to assess several aspects of this top spread powder layer. Using different measurement procedures, the roughness of the top layer, the surface coverage of a single spread powder layer and the powder bed density of an entire spreading experiment can be determined. Since the tester is freely programmable, the individual process steps of spreading a single powder layer can also be varied. Using these methods, the influence of different process parameters such as e.g. the spreading velocity or the distance between the blade and the building platform, which is also referred to as gap size in general, on the quality of the top or only a single spread layer and on the powder bed packing density can be examined. This study presents the new test device as well as the corresponding measurement procedures mentioned, the reproducibility of the results, which, depending on the measurement method and the measured parameter, range between 0.24 and 4.81%, and the influence of the spreading strategy, which defines the chronological order of the single steps during spreading.","PeriodicalId":20392,"journal":{"name":"Powder Metallurgy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42601200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-21DOI: 10.1080/00325899.2022.2041787
A. S. Shaikh, M. Rashidi, Kevin Minet-Lallemand, E. Hryha
ABSTRACT Increased adoption of additively manufactured superalloys has led to the consideration of revised heat treatment approaches for these materials. The rapid cooling during additive manufacturing processes has been seen to suppress gamma prime (γ′) precipitation, which has raised the possibilities for omitting the high-temperature solution treatment step that usually precedes ageing heat treatment for these alloys. In this work, the as-built microstructure of a high gamma prime fraction superalloy Inconel 939 is presented, where the absence of any γ′ precipitation is notable. However, transmission electron microscopy shows the presence of nano-sized Eta (η) phase. It is shown that the omission of solution treatment leads to the growth of the deleterious η phase upon ageing, which results in embrittlement in tensile loading. It is concluded that at least for this particular alloy the solution treatment plays a critical role in the establishment of the required microstructure and hence cannot be omitted from the heat treatment.
{"title":"On as-built microstructure and necessity of solution treatment in additively manufactured Inconel 939","authors":"A. S. Shaikh, M. Rashidi, Kevin Minet-Lallemand, E. Hryha","doi":"10.1080/00325899.2022.2041787","DOIUrl":"https://doi.org/10.1080/00325899.2022.2041787","url":null,"abstract":"ABSTRACT Increased adoption of additively manufactured superalloys has led to the consideration of revised heat treatment approaches for these materials. The rapid cooling during additive manufacturing processes has been seen to suppress gamma prime (γ′) precipitation, which has raised the possibilities for omitting the high-temperature solution treatment step that usually precedes ageing heat treatment for these alloys. In this work, the as-built microstructure of a high gamma prime fraction superalloy Inconel 939 is presented, where the absence of any γ′ precipitation is notable. However, transmission electron microscopy shows the presence of nano-sized Eta (η) phase. It is shown that the omission of solution treatment leads to the growth of the deleterious η phase upon ageing, which results in embrittlement in tensile loading. It is concluded that at least for this particular alloy the solution treatment plays a critical role in the establishment of the required microstructure and hence cannot be omitted from the heat treatment.","PeriodicalId":20392,"journal":{"name":"Powder Metallurgy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45172534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-17DOI: 10.1080/00325899.2022.2040699
Xuan Zhou, Mingjia Wang
ABSTRACT In the present work, a novel method was first proposed to realise direct powder forging of high borated stainless steel on Gleeble through hot compression tests performed at 1150°C and 0.01–10 s−1 with strains of 32% and 50%. Particle deformation and microstructural evolution of high borated stainless steel powder during direct forging were investigated. Backscattered electron (BSE) and electron backscatter diffraction (EBSD) were employed for microstructure examination. Microstructure reveals that large deformation zones were easily distinguished by boride and grain features. Enhanced boride coarsening in the contact area of powders was attributed to the combined action of strain, dislocation, stress and temperature rising. Strain rates had no obvious influence on densification but significantly affected the deformation of particles. Furthermore, the mechanism of particle deformation enhanced by a higher strain rate was discussed.
{"title":"Particle deformation and microstructural evolution of high borated stainless steel consolidated by Gleeble-simulated direct powder forging","authors":"Xuan Zhou, Mingjia Wang","doi":"10.1080/00325899.2022.2040699","DOIUrl":"https://doi.org/10.1080/00325899.2022.2040699","url":null,"abstract":"ABSTRACT In the present work, a novel method was first proposed to realise direct powder forging of high borated stainless steel on Gleeble through hot compression tests performed at 1150°C and 0.01–10 s−1 with strains of 32% and 50%. Particle deformation and microstructural evolution of high borated stainless steel powder during direct forging were investigated. Backscattered electron (BSE) and electron backscatter diffraction (EBSD) were employed for microstructure examination. Microstructure reveals that large deformation zones were easily distinguished by boride and grain features. Enhanced boride coarsening in the contact area of powders was attributed to the combined action of strain, dislocation, stress and temperature rising. Strain rates had no obvious influence on densification but significantly affected the deformation of particles. Furthermore, the mechanism of particle deformation enhanced by a higher strain rate was discussed.","PeriodicalId":20392,"journal":{"name":"Powder Metallurgy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41876772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT (FeCoCrNi)100-3xTixB2x (x = 0, 1, 2 and 6 at.-%) high entropy alloys (HEAs) were fabricated by hot pressing. The effects of Ti and B content on the microstructure and mechanical properties were investigated using X-ray electron diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The results show that the FeCoCrNi high-entropy alloy form single FCC phase. With the increase of Ti and B content, dual FCC phases appeared in the alloys. Additionally, the per cent elongation of alloys first increased and then declined, while the ultimate tensile strength kept moving up. The (FeCoCrNi)97TiB2 alloy has the highest per cent elongation of 13.1%, which is more than three times that of the FeCoCrNi. the (FeCoCrNi)82Ti6B12 alloy shows the highest ultimate tensile strength, which is 646.5 ± 0.1 MPa. The enhanced strength is attributed to solid solution effect and Orowan process.
{"title":"Effect of Ti and B additions on the microstructure and properties of FeCoCrNi high entropy alloys prepared by hot pressing","authors":"Yicheng Zhang, Yanru Yang, Jifeng Zhang, Jiawen Li, He-guo Zhu, Zonghan Xie","doi":"10.1080/00325899.2022.2029302","DOIUrl":"https://doi.org/10.1080/00325899.2022.2029302","url":null,"abstract":"ABSTRACT (FeCoCrNi)100-3xTixB2x (x = 0, 1, 2 and 6 at.-%) high entropy alloys (HEAs) were fabricated by hot pressing. The effects of Ti and B content on the microstructure and mechanical properties were investigated using X-ray electron diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The results show that the FeCoCrNi high-entropy alloy form single FCC phase. With the increase of Ti and B content, dual FCC phases appeared in the alloys. Additionally, the per cent elongation of alloys first increased and then declined, while the ultimate tensile strength kept moving up. The (FeCoCrNi)97TiB2 alloy has the highest per cent elongation of 13.1%, which is more than three times that of the FeCoCrNi. the (FeCoCrNi)82Ti6B12 alloy shows the highest ultimate tensile strength, which is 646.5 ± 0.1 MPa. The enhanced strength is attributed to solid solution effect and Orowan process.","PeriodicalId":20392,"journal":{"name":"Powder Metallurgy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45542248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT In this study, WMoTaTi refractory high-entropy alloy was successfully fabricated via selective laser melting (SLM) using pre-alloyed powders by mechanical milling combined with gas–solid fluidisation. Fluidisation effectively improves the particle sphericity and thus its spreading performance suitable for SLM. Processing parameters were investigated in terms of laser power, hatching space and scanning rate. The relative density of WMoTaTi made by SLM (SLMed) reaches 95.8 ± 1.4%, and it consisted of dominant BCC phase and minor HCP phase. The slight precipitation of HCP Ti was driven due to the non-equilibrium solidification during ultra-rapid cooling by SLM. The microhardness of WMoTaTi via SLM is 617.2 ± 4.1 HV, preferable to those fabricated by traditional manufacturing processes. The sound microhardness is resulted from the fine grain size and nano-sized HCP precipitates, which favour dislocation pinning and promote strength. This work demonstrates that SLMed WMoTaTi has sound mechanical properties while using the cost-affordable pre-alloyed powders by fluidisation.
{"title":"Additive manufacturing of WMoTaTi refractory high-entropy alloy by employing fluidised powders","authors":"Chang Liu, Keya Zhu, Wangwang Ding, Yu Liu, Gang Chen, X. Qu","doi":"10.1080/00325899.2022.2031718","DOIUrl":"https://doi.org/10.1080/00325899.2022.2031718","url":null,"abstract":"ABSTRACT\u0000 In this study, WMoTaTi refractory high-entropy alloy was successfully fabricated via selective laser melting (SLM) using pre-alloyed powders by mechanical milling combined with gas–solid fluidisation. Fluidisation effectively improves the particle sphericity and thus its spreading performance suitable for SLM. Processing parameters were investigated in terms of laser power, hatching space and scanning rate. The relative density of WMoTaTi made by SLM (SLMed) reaches 95.8 ± 1.4%, and it consisted of dominant BCC phase and minor HCP phase. The slight precipitation of HCP Ti was driven due to the non-equilibrium solidification during ultra-rapid cooling by SLM. The microhardness of WMoTaTi via SLM is 617.2 ± 4.1 HV, preferable to those fabricated by traditional manufacturing processes. The sound microhardness is resulted from the fine grain size and nano-sized HCP precipitates, which favour dislocation pinning and promote strength. This work demonstrates that SLMed WMoTaTi has sound mechanical properties while using the cost-affordable pre-alloyed powders by fluidisation.","PeriodicalId":20392,"journal":{"name":"Powder Metallurgy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48498949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-28DOI: 10.1080/00325899.2022.2029303
Nattawood Suesawadwanid, A. Khantachawana, Kasama Srirussamee, K. Kondoh
ABSTRACT Titanium-niobium (Ti-Nb) alloys have been extensively studied for medical implants due to their advantageous mechanical properties and biocompatibility. However, the stress shielding effect remains a challenge. This research investigated the effects of Nb content and enhancement of α′′ formation on the mechanical properties of Ti-xNb alloys (x = 0, 5, 15 and 25%) fabricated by spark plasma sintering. Water quenching from the β phase induced α′′ phase formation in Ti-5Nb and Ti-15Nb samples, thereby reducing their Young’s modulus values but was not observed in commercially pure titanium (CP-Ti) and Ti-25Nb. Results showed that heat treatment with water quenching induced α′′ phase formation and can be used to tailor the properties of Ti-Nb alloys fabricated by SPS. This technique can also be used to enhance material ductility at high β-stabilizer content, as observed in Ti-25Nb samples.
{"title":"Effect of Nb Content and water quenching on microstructure and mechanical properties of Ti-Nb alloys fabricated by spark plasma sintering","authors":"Nattawood Suesawadwanid, A. Khantachawana, Kasama Srirussamee, K. Kondoh","doi":"10.1080/00325899.2022.2029303","DOIUrl":"https://doi.org/10.1080/00325899.2022.2029303","url":null,"abstract":"ABSTRACT Titanium-niobium (Ti-Nb) alloys have been extensively studied for medical implants due to their advantageous mechanical properties and biocompatibility. However, the stress shielding effect remains a challenge. This research investigated the effects of Nb content and enhancement of α′′ formation on the mechanical properties of Ti-xNb alloys (x = 0, 5, 15 and 25%) fabricated by spark plasma sintering. Water quenching from the β phase induced α′′ phase formation in Ti-5Nb and Ti-15Nb samples, thereby reducing their Young’s modulus values but was not observed in commercially pure titanium (CP-Ti) and Ti-25Nb. Results showed that heat treatment with water quenching induced α′′ phase formation and can be used to tailor the properties of Ti-Nb alloys fabricated by SPS. This technique can also be used to enhance material ductility at high β-stabilizer content, as observed in Ti-25Nb samples.","PeriodicalId":20392,"journal":{"name":"Powder Metallurgy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46768255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT This paper used carbonyl iron powder and carbide powder as raw materials to prepare high carbon M2 powder metallurgy high-speed steel through the cold compaction-sintering method. The evolution of microstructure and properties of the material at different sintering temperatures were emphatically studied. The results show that: The microstructure of the samples is that different types of carbides are uniformly dispersed in the matrix. Since the dissolution of the original carbides is a continuous process, the precipitated carbides are constantly changing with the increase of sintering temperature. Moreover, M2 steel achieves sintering densification near the solidus temperature, the sintering window is expanded to 10–15°C. In the sintering temperature range, the carbides in the samples are fine and uniformly dispersed. The material sintered at 1225°C has the best mechanical properties, with a bending strength of 2754 MPa, and a hardness of 51 HRC. In addition, mechanical properties are greatly improved by heat treatment.
{"title":"Microstructure and mechanical properties of high carbon M2 powder metallurgy high-speed steel prepared by the carbide addition","authors":"Jun-de Yang, Ru-tie Liu, X. Xiong, Huaizhuang Luan, Yan-Zhao Hao, Baozhen Yang, Jie Chen","doi":"10.1080/00325899.2022.2027593","DOIUrl":"https://doi.org/10.1080/00325899.2022.2027593","url":null,"abstract":"ABSTRACT This paper used carbonyl iron powder and carbide powder as raw materials to prepare high carbon M2 powder metallurgy high-speed steel through the cold compaction-sintering method. The evolution of microstructure and properties of the material at different sintering temperatures were emphatically studied. The results show that: The microstructure of the samples is that different types of carbides are uniformly dispersed in the matrix. Since the dissolution of the original carbides is a continuous process, the precipitated carbides are constantly changing with the increase of sintering temperature. Moreover, M2 steel achieves sintering densification near the solidus temperature, the sintering window is expanded to 10–15°C. In the sintering temperature range, the carbides in the samples are fine and uniformly dispersed. The material sintered at 1225°C has the best mechanical properties, with a bending strength of 2754 MPa, and a hardness of 51 HRC. In addition, mechanical properties are greatly improved by heat treatment.","PeriodicalId":20392,"journal":{"name":"Powder Metallurgy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44851547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-13DOI: 10.1080/00325899.2022.2026031
T. Varol, O. Güler, Serhatcan Berk Akçay, Hüseyin Can Aksa
ABSTRACT In this study, copper powders with dendritic morphology were produced by the electrolysis method, and then silver coating was applied to these powders by an electroless coating method. The bulk samples were fabricated by hot pressing method using different ratios of copper and silver-plated copper powders. The results showed that the electroless silver coating layer provided a strong bond at the particle boundaries of the samples, significantly improving the physical and mechanical properties of the materials. Accordingly, the hardness, tensile strength, electrical and thermal conductivity values of the samples produced from silver-plated dendritic copper particles were determined to be approximately 98 HB, 185 MPa, 102 IACS% and 402 W mK−1, respectively. In addition, the oxidation resistance of the sample produced from completely silver-coated copper powders is 4 times higher than that of pure copper.
摘要本研究采用电解法制备枝晶铜粉，然后采用化学镀银的方法在其表面镀银。采用热压法制备了不同配比的铜粉和镀银铜粉。结果表明，化学镀银层在样品的颗粒边界处形成了牢固的结合，显著提高了材料的物理力学性能。因此，由镀银枝晶铜颗粒制成的样品的硬度、抗拉强度、电导率和导热系数分别约为98 HB、185 MPa、102 IACS%和402 W mK−1。此外，由完全镀银的铜粉制成的样品的抗氧化性比纯铜高4倍。
{"title":"Novel advanced copper-silver materials produced from recycled dendritic copper powders using electroless coating and hot pressing","authors":"T. Varol, O. Güler, Serhatcan Berk Akçay, Hüseyin Can Aksa","doi":"10.1080/00325899.2022.2026031","DOIUrl":"https://doi.org/10.1080/00325899.2022.2026031","url":null,"abstract":"ABSTRACT In this study, copper powders with dendritic morphology were produced by the electrolysis method, and then silver coating was applied to these powders by an electroless coating method. The bulk samples were fabricated by hot pressing method using different ratios of copper and silver-plated copper powders. The results showed that the electroless silver coating layer provided a strong bond at the particle boundaries of the samples, significantly improving the physical and mechanical properties of the materials. Accordingly, the hardness, tensile strength, electrical and thermal conductivity values of the samples produced from silver-plated dendritic copper particles were determined to be approximately 98 HB, 185 MPa, 102 IACS% and 402 W mK−1, respectively. In addition, the oxidation resistance of the sample produced from completely silver-coated copper powders is 4 times higher than that of pure copper.","PeriodicalId":20392,"journal":{"name":"Powder Metallurgy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48795436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-03DOI: 10.1080/00325899.2021.2020486
Alberto Cabo Rios, E. Hryha, E. Olevsky, P. Harlin
ABSTRACT Green density of binder jetted parts are typically equal or lower than the powder tap density. Also, anisotropic green porosity distribution is expected because of the characteristics of the binder jetting (BJ) printing process. In this study, the microstructure evolution in terms of phases and porosity characteristics was studied. A transition from irregular-shape interconnected porosity in pre-sintered samples to closed quasi-spherical porosity for samples sintered at 1370°C was observed. EBSD phase map showed ∼2.73% of δ-ferrite in sample sintered at 1370°C. The anisotropic porosity distribution was revealed by a higher area fraction of aligned large pores (>35 µm), within the cross-section perpendicular to the building direction. Chemical analysis showed an increase of C, O and N on the green sample, while a strong decrease was found after sintering when compared with the powder chemistry. δ-ferrite onset, from phase equilibrium calculations, varies from ∼1250°C (sintered sample chemistry) to ∼1350°C (powder chemistry).
{"title":"Sintering anisotropy of binder jetted 316L stainless steel: part II – microstructure evolution during sintering","authors":"Alberto Cabo Rios, E. Hryha, E. Olevsky, P. Harlin","doi":"10.1080/00325899.2021.2020486","DOIUrl":"https://doi.org/10.1080/00325899.2021.2020486","url":null,"abstract":"ABSTRACT Green density of binder jetted parts are typically equal or lower than the powder tap density. Also, anisotropic green porosity distribution is expected because of the characteristics of the binder jetting (BJ) printing process. In this study, the microstructure evolution in terms of phases and porosity characteristics was studied. A transition from irregular-shape interconnected porosity in pre-sintered samples to closed quasi-spherical porosity for samples sintered at 1370°C was observed. EBSD phase map showed ∼2.73% of δ-ferrite in sample sintered at 1370°C. The anisotropic porosity distribution was revealed by a higher area fraction of aligned large pores (>35 µm), within the cross-section perpendicular to the building direction. Chemical analysis showed an increase of C, O and N on the green sample, while a strong decrease was found after sintering when compared with the powder chemistry. δ-ferrite onset, from phase equilibrium calculations, varies from ∼1250°C (sintered sample chemistry) to ∼1350°C (powder chemistry).","PeriodicalId":20392,"journal":{"name":"Powder Metallurgy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42901867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：