Effects of Powder Molding Process on the Microstructure and Mechanical Properties of As-Sintered Ultrafine- Grained WC-12Co Cemented Carbides

doi:10.11900/0412.1961.2024.00013

Acta Metall Sin

2025, Vol. 61

Issue (10): 1579-1592 DOI: 10.11900/0412.1961.2024.00013

Research paper

Current Issue | Archive | Adv Search

Effects of Powder Molding Process on the Microstructure and Mechanical Properties of As-Sintered Ultrafine- Grained WC-12Co Cemented Carbides

WANG Chao, WANG Haibin(

), XUAN Shilei, LIU Xuan, LIU Xuemei, SONG Xiaoyan(

)

Key Laboratory of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China

Cite this article:

WANG Chao, WANG Haibin, XUAN Shilei, LIU Xuan, LIU Xuemei, SONG Xiaoyan. Effects of Powder Molding Process on the Microstructure and Mechanical Properties of As-Sintered Ultrafine- Grained WC-12Co Cemented Carbides. Acta Metall Sin, 2025, 61(10): 1579-1592.

Download:

HTML

PDF(5076KB)
Export: BibTeX | EndNote (RIS)

Abstract

The quality of the green body is crucial for achieving excellent mechanical properties in sintered cemented carbides via the powder metallurgy process, making it necessary to explore and optimize the powder molding process. In this study, the effects of the content and solution concentration of the pressing binder, as well as the green density during the powder molding process, on the geometries, microstructures, and mechanical properties of sintered WC-12Co cemented carbides were investigated. These materials were produced using in situ synthesized ultrafine WC-Co composite powder as the raw material. The results indicated that increasing the polyethylene glycol (PEG) content as the pressing binder within a certain range led to a linear increase in the magnetic Co content of the sintered cemented carbides. The concentration of the PEG solution primarily influenced its dispersion in the powder and feedstock particle size. Both of which considerably influenced the phase constitution, density, and mechanical properties of the prepared cemented carbides. During the pressing process, as the green density increased within a certain range, the shrinkage rate of the sintered alloys exhibited a good linear relationship with it. Additionally, the density of the cemented carbides initially increased notably and then stabilized, whereas the fracture strength initially increased and then decreased. By optimizing the conditions to 1.5% PEG content, 4.1% PEG concentration, and a green density of 7.7 g/cm³, the sintered cemented carbide achieved an exceptional average transverse rupture strength of 4571 MPa with minimal fluctuations in the measured values. The formation of numerous Co-rich nanophases within the WC grains, which hinder dislocation movement, is the primary reason for the enhanced strength of the cemented carbide.

Key words: cemented carbide pressing binder green density mechanical property strengthening mechanism

Received: 17 January 2024

ZTFLH:

TG135

Fund: National Key Research and Development Program of China(2022YFB3708800);National Natural Science Foundation of China(52171061);National Natural Science Foundation of China(92163107);National Natural Science Foundation of China(52101032)

	Service

	E-mail this article
	Add to citation manager
	E-mail Alert
	RSS
	（）
	Articles by authors
	WANG Chao
	WANG Haibin
	XUAN Shilei
	LIU Xuan
	LIU Xuemei
	SONG Xiaoyan

URL:

https://www.ams.org.cn/EN/10.11900/0412.1961.2024.00013 OR https://www.ams.org.cn/EN/Y2025/V61/I10/1579

Fig.1 SEM images and WC grain size distributions (insets) (a-g) of the sintered WC-12Co cemented carbides with polyethylene glycol (PEG) contents of 1.0% (a, f, g), 1.5% (b), 2.0% (c), 2.5% (d), and 3.0% (e); and corresponding XRD spactra of the cemented carbide specimens (h) (Figs.1f and g show the abnormal WC grain growth and the presence of pores (indicated by circles) in the specimen prepared with 1.0%PEG, respectively)

Fig.2 Densities of the green bodies and shrinkage rates along vertical and parallel pressure directions (a) and mass fraction of magnetic Co (b) of the sintered WC-12Co cemented carbides with different amounts of PEG addition during the molding process

Fig.3 Variations of hardness and fracture toughness (a), and transverse rupture strength (b) of the sintered WC-12Co cemented carbides with different amounts of PEG addition during the molding process

Fig.4 Variations of the green densities and shrinkage rates along vertical and parallel pressure directions of the sintered WC-12Co cemented carbides with different PEG solution concentra-tions at PEG content of 1.5% during the molding process (Insets show the corresponding macro-morphologies of the powders mixed with PEG solution)

Fig.5 OM images of the sintered WC-12Co cemented carbides with PEG solution concentrations of 4.1% (a) and 30.0% (b) at PEG content of 1.5%; and corresponding XRD spectra of the cemented carbide (c) (Circles in Fig.5b show the poro-sities)

Fig.6 Variations of hardness and fracture toughness (a), and transverse rupture strength (c) of the sintered WC-12Co cemented carbides with different PEG solution concentrations at PEG content of 1.5% during the molding process

Fig.7 Crack propagation paths in the sintered WC-12Co cemented carbides with PEG solution concentrations of 4.1% (a) and 30.0% (b) at PEG content of 1.5%; and statistical analysis of the crack propagation paths (c) (Yellow lines in Figs.7a and b indicate the intragranular fracture along the WC/WC grain boundaries or the WC/Co phase boundaries, and the red lines indicate the transgranular fracture of WC grains)

Fig.8 SEM fracture images of the sintered WC-12Co cemented carbides with PEG solution concentrations of 4.1% (a, b) and 30.0% (c-e) at PEG content of 1.5% under different magnifications (Insets show the locally enlarged images)

Fig.9 Relationships between the filling amount of powder in the mould and the green density (a) and the shrinkage rates along vertical and parallel pressure directions and relative densities of the sintered WC-12Co cemented carbides with different green densities (b) under PEG content of 1.5% and PEG solution concentration of 4.1%

Fig.10 Effects of green density on mechanical properties of the sintered WC-12Co cemented carbides under PEG content of 1.5% and PEG solution concentration of 4.1%

Fig.11 Microstructural analyses of the sintered WC-12Co cemented carbides under PEG content of 1.5% and PEG solution concentration of 4.1%
(a) STEM-HAADF image and elemental mapping results
(b) sub-grain structure of WC grain
(c) grain size distribution of Co-rich phases inside the WC grains in Fig.11b

Fig.12 Microstructural analyses of the sintered WC-12Co cemented carbides under PEG content of 1.5% and PEG solution concentration of 30.0%
(a) STEM-HAADF image and elemental mapping results
(b) sub-grain structure of WC grain
(c) grain size distribution of Co-rich phases inside the WC grains in Fig.12b

Table 1 EDS analysis results of the Co binder phase in the sintered WC-12Co cemented carbides at PEG content of 1.5% with different PEG solution concentrations

Fig.13 TEM fracture analyses of the sintered WC-12Co cemented carbides under PEG content of 1.5% and PEG concentra-tion of 4.1%
(a) bright-field TEM image and elemental mapping results of W, C, Co, and Cr of the circle region
(b) HRTEM image of the interface between a Co-rich particle of about 100 nm and the WC matrix, and corresponding fast Fourier transform of regions A and B
(c) HRTEM image of the interface between a Co-rich particle of about 10 nm and the WC matrix, and corresponding fast Fourier transform of regions C and D

[1]	Wang K W, Zhao K, Liu J L, et al. Interplay of microstructure and mechanical properties of WC-6Co cemented carbides by hot oscillating pressing method [J]. Ceram. Int., 2021, 47: 20731
[2]	Ke Z, Zheng Y, Zhang G T, et al. Microstructure and mechanical properties of dual-grain structured WC-Co cemented carbides [J]. Ceram. Int., 2019, 45: 21528 doi: 10.1016/j.ceramint.2019.07.146
[3]	Li M, Gong M F, Zhang C Y, et al. Research progress of sintering technique of ultrafine and Nano WC-Co cemented carbides [J]. Mater. Rep., 2020, 34: 15138
	李萌, 弓满锋, 张程煜等. 超细、纳米晶WC-Co硬质合金烧结技术的研究现状 [J]. 材料导报, 2020, 34: 15138
[4]	Yang J, Roa J J, Odén M, et al. 3D FIB/FESEM tomography of grinding-induced damage in WC-Co cemented carbides [J]. Procedia CIRP, 2020, 87: 385
[5]	Saai A, Bjørge R, Dahl F, et al. Adaptation of laboratory tests for the assessment of wear resistance of drill-bit inserts for rotary-percussive drilling of hard rocks [J]. Wear, 2020, 456-457: 203366
[6]	Ding Q J, Zheng Y, Ke Z, et al. Effects of fine WC particle size on the microstructure and mechanical properties of WC-8Co cemented carbides with dual-scale and dual-morphology WC grains [J]. Int. J. Refract. Met. Hard Mater., 2020, 87: 105166
[7]	Ortner H M, Ettmayer P, Kolaska H, et al. The history of the technological progress of hardmetals [J]. Int. J. Refract. Met. Hard Mater., 2015, 49: 3
[8]	Martins V, Rodrigues W C, Ferrandini P L, et al. Comparative studies of WC-Co and WC-Co-Ni composites obtained by conventional powder metallurgy [J]. Mater. Res., 2011, 14: 274
[9]	Stanciu V I, Erauw J P, Boilet L, et al. WC-Co composite made with doped binder: The effect of binder proportion on microstructure and mechanical properties [J]. Int. J. Refract. Met. Hard Mater., 2023, 112: 106161
[10]	Guo X H. The latest study on extrusion molding binder and production technology of cemented carbide [J]. Rare Met. Cem. Carbides, 2014, 42(6): 46
	郭幸华. 硬质合金挤压成形剂及生产技术研究进展 [J]. 稀有金属与硬质合金, 2014, 42(6): 46
[11]	Du W C, Ren X R, Pei Z J, et al. Ceramic binder jetting additive manufacturing: A literature review on density [J]. J. Manuf. Sci. Eng., 2020, 142: 040801
[12]	Chen C Y. Research of effects of paraffin as pressing binder on properties of cemented carbide [J]. Fujian Metall., 2016, (5): 42
	陈成艺. 石蜡成形剂改性对硬质合金影响的研究 [J]. 福建冶金, 2016, (5): 42
[13]	Chen S L, Fu K, Zhou J H, et al. Study on improvement of paraffin as the molding agent of cemented carbide [J]. Rare Met. Cem. Carbides, 2014, 42(3): 58
	陈双琳, 付坤, 周建华等. 硬质合金成形剂石蜡的改进研究 [J]. 稀有金属与硬质合金, 2014, 42(3): 58
[14]	Liu J, Liu A H, Liu Y X, et al. Effect of 56# paraffin wax and PEG4000 on formability of cemented carbide inserts [J]. Cem. Carbides, 2023, 40: 134
	刘娟, 刘安虎, 刘雅璇等. 56#石蜡和PEG 4000对硬质合金数控刀片成型性能的影响 [J]. 硬质合金, 2023, 40: 134
[15]	Qu X H, Gao J X, Qin M L, et al. Application of a wax-based binder in PIM of WC-TiC-Co cemented carbides [J]. Int. J. Refract. Met. Hard Mater., 2005, 23: 273
[16]	Eso O, Wang X, Wolf S, et al. Property correlations of WC-Co with modified binders [J]. Int. J. Refract. Met. Hard Mater., 2024, 118: 106482.
[17]	Meng X W. Research on performance of new pressing binder in hardmetal [J]. Adv. Mater. Res., 2010, 148-149: 1730
[18]	Sun D, Li G S, Lin C F, et al. Research on pre-debinding process of binders for ultrafine cemented carbide bar extrusion molding [J]. Powder Metall. Technol., 2010, 28: 262
	孙丹, 李广生, 林春芳等. 超细硬质合金棒料挤压成形剂预脱除工艺研究 [J]. 粉末冶金技术, 2010, 28: 262
[19]	Hong H X, Sun A K, Wang D Z. Application of a new pressing binder composed of stearic acid and alcohol-soluble polyurethane resin [J]. Cem. Carbide, 2023, 40: 347
	洪海侠, 孙翱魁, 王德志. 硬脂酸-醇溶性聚氨酯树脂新型成型剂的应用研究 [J]. 硬质合金, 2023, 40: 347
[20]	Zwiren A D, Murphy T F. Comparison of SS-316L PM material processed via binder jetting with SS-316L powder processed by pressing and sintering [J]. Int. J. Powder Metall., 2018, 54: 39
[21]	Zhang W F. Study on preparation of ultrafine hardmetal rods [D]. Wuhan: Wuhan University of Technology, 2004
	张卫丰. 超细硬质合金棒材的制备研究 [D]. 武汉: 武汉理工大学, 2004
[22]	Zhao L L, Zhang Y, Feng W, et al. Effect of shrinkage coefficient on compaction and physical property of cemented carbide die forming [J]. Tool Eng., 2019, 53(9): 62
	赵丽丽, 张严, 冯文等. 硬质合金模压成型收缩系数对压制性能与物理性能的影响 [J]. 工具技术, 2019, 53(9): 62
[23]	Liu W B, Song X Y, Zhang J X, et al. Preparation of ultrafine WC-Co composite powder by in situ reduction and carbonization reactions [J]. Int. J. Refract. Met. Hard Mater., 2009, 27: 115
[24]	Liu X W, Song X Y, Wang H B, et al. Complexions in WC-Co cemented carbides [J]. Acta Mater., 2018, 149: 164
[25]	Meng X W, Xu T. Application research on a new pressing binder for cemented carbide [J]. Cem. Carbide, 2011, 28: 158
	孟小卫, 徐涛. 新型硬质合金成型剂应用研究 [J]. 硬质合金, 2011, 28: 158
[26]	Zhu E T. Study on the preparation and properties of Nano WC-Co composite powder by in-situ synthesis and high performance cemented carbide [D]. Hefei: Hefei University of Technology, 2021
	朱二涛. 原位合成纳米WC-Co复合粉末及高性能硬质合金制备和性能研究 [D]. 合肥: 合肥工业大学, 2021
[27]	Zhao C, Lu H, Wang H B, et al. Seeding ductile nanophase in ceramic grains [J]. Mater. Horiz., 2024, 11: 1908 doi: 10.1039/d3mh02233a pmid: 38334032

[1]	ZHANG Tianyu, ZHANG Peng, XIAO Na, WANG Xiaohai, LIU Guoqiang, YANG Zhigang, ZHANG Chi. Effect of Austenitizing Temperature on the Microstructure and Mechanical Properties of a 2 GPa Ultra-High Strength Steel[J]. 金属学报, 2025, 61(9): 1353-1363.
[2]	WANG Hongying, YAO Zhihao, LI Dayu, GUO Jing, YAO Kaijun, DONG Jianxin. Similarities and Differences of Microstructure and Mechanical Properties Between High γ' Content Powder and Wrought Superalloys[J]. 金属学报, 2025, 61(9): 1364-1374.
[3]	WU Zhiyong, SHAO Huifan, CAI Changchun, ZENG Min, WANG Zhenjun, WANG Yanli, CHEN Lei, XIONG Bowen. Tensile and Fracture Behaviors of Stitched Twill Carbon Fabric Structure Reinforced Aluminum Matrix Composites at Elevated Temperature[J]. 金属学报, 2025, 61(9): 1387-1402.
[4]	XIAO Wenlong, ZANG Chenyang, GUO Jintao, FENG Jiawen, MA Chaoli. Two-Stage Aging Process of 7A65 Aluminum Alloy Thick Plate Based on In Situ Resistance Method[J]. 金属学报, 2025, 61(8): 1153-1164.
[5]	LIU Jihao, CHI Hongxiao, WU Huibin, MA Dangshen, ZHOU Jian, GU Jinbo. Influence of Spray Forming Process on Carbide Characteristics and Mechanical Properties of M3 High-Speed Steel[J]. 金属学报, 2025, 61(8): 1229-1244.
[6]	XIE Ang, CHEN Shenghu, JIANG Haichang, RONG Lijian. Effects of Nb Content and Homogenization Treatment on the Microstructure and Mechanical Properties of Cast Austenitic Stainless Steel[J]. 金属学报, 2025, 61(7): 1035-1048.
[7]	GE Penghua, ZHANG Yong, LI Zhiming. Soft-Magnetic and Mechanical Behaviors of Heterostructured FeCoNi Medium-Entropy Alloys[J]. 金属学报, 2025, 61(7): 1119-1128.
[8]	QIN Lanyun, ZHANG Jian, YI Junzhen, CUI Yanfeng, YANG Guang, WANG Chao. Effects of Solution Aging on Microstructural Evolution and Mechanical Properties of Laser Deposition Repairing ZM6 Alloy[J]. 金属学报, 2025, 61(6): 875-886.
[9]	LI Fushun, LIU Zhipeng, DING Cancan, HU Bin, LUO Haiwen. Strengthening and Plastifying Mechanisms of a Novel High-Strength Low-Density Austenitic Steel[J]. 金属学报, 2025, 61(6): 909-916.
[10]	LEI Yunlong, YANG Kang, XIN Yue, JIANG Zitao, TONG Baohong, ZHANG Shihong. Microstructure Evolution of Mechanically-Alloying and Its Subsequently-Annealed AlCrCu_0.5Mo_0.5Ni High-Entropy Alloy[J]. 金属学报, 2025, 61(5): 731-743.
[11]	MENG Xianglong, LIU Ruiliang, Li D. Y.. First Principles Study on the Precipitation and Properties of Carbides in the Surface Carburized Layer of Tantalum Alloys[J]. 金属学报, 2025, 61(5): 797-808.
[12]	SUN Jun, LIU Gang, YANG Chong, ZHANG Peng, XUE Hang. Heat-Resistant Al Alloys: Microstructural Design and Preparation[J]. 金属学报, 2025, 61(4): 521-525.
[13]	YANG Minghui, LI Xingwu, SUN Chonghao, RUAN Ying. Microstructure and Mechanical Properties of Monel K-500 Alloy in Synergetic Modulation of Directional Solidification and Thermal Processing[J]. 金属学报, 2025, 61(4): 561-571.
[14]	CAI Zhengqing, YIN Dawei, YANG Liang, WANG Wenxiang, WANG Feilong, WEN Yongqing, MA Mingzhen. Effect of Ag Substitution of Cu on Properties of Zr-Ti-Cu-Al Amorphous Alloys[J]. 金属学报, 2025, 61(4): 572-582.
[15]	OUYANG Sihui, SHE Jia, CHEN Xianhua, PAN Fusheng. Preparation of Biodegradable Mg-Based Composites and Their Recent Advances in Orthopedic Applications[J]. 金属学报, 2025, 61(3): 455-474.

No Suggested Reading articles found!

Viewed

Full text

Abstract

Cited

Shared

Discussed