兩相區位錯增殖對低碳貝氏體/鐵素體復相鋼組織和性能的影響

田亞強; 田耕; 王安東; 鄭小平; 魏英立; 宋進英; 陳連生

doi:10.13374/j.issn2095-9389.2019.03.005

兩相區位錯增殖對低碳貝氏體/鐵素體復相鋼組織和性能的影響

doi: 10.13374/j.issn2095-9389.2019.03.005

華北理工大學教育部現代冶金技術重點實驗室, 唐山 063009

基金項目:

國家自然科學基金資助項目 51574107

河北省自然科學基金資助項目 E2016209048

河北省自然科學基金資助項目 E2017209048

河北省高等學校科學技術研究資助項目 QN2016185

唐山市科技創新團隊培養計劃資助項目 15130202C

詳細信息

通訊作者:
陳連生, E-mail: zyzx@ncst.edu.cn

中圖分類號: TG142.2
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出版歷程
- 收稿日期: 2017-07-11
- 刊出日期: 2019-03-20

Effect of dislocation multiplication in intercritical region on microstructure and properties of low-carbon bainite/ferrite multiphase steel

Key Laboratory of the Ministry of Education for Modern Metallurgy Technology, North China University of Science and Technology, Tangshan 063009, China

More Information

Corresponding author: CHEN Lian-sheng E-mail: zyzx@ncst.edu.cn

摘要

摘要: 利用掃描電子顯微鏡(SEM)、透射電子顯微鏡(TEM)、電子探針(EPMA)、X射線衍射儀(XRD)、室溫拉伸等手段, 通過兩相區保溫-淬火(IQ)、兩相區形變后保溫-淬火(DIQ)、兩相區保溫-淬火-配分-貝氏體區等溫(IQ&PB)及兩相區形變后保溫-淬火-配分-貝氏體區等溫(DIQ&PB)熱處理工藝, 研究高溫形變對室溫組織、性能、殘余奧氏體穩定性的綜合影響作用.結果表明, 經15%的壓縮形變后鐵素體中位錯密度由0.290×10¹⁴增加至1.286×10¹⁴ m^-2, 馬氏體(原奧氏體)中C、Cu元素富集濃度提高, 高溫形變產生位錯增殖對元素配分有明顯促進作用.DIQ&PB工藝下, 形變后貝氏體板條尺寸變短且寬度增加0.1 μm左右, 貝氏體轉變量較未變形時增加14%, 多邊形鐵素體尺寸明顯減小.力學性能方面, 兩相區形變熱處理后抗拉強度增加132.85 MPa, 斷后伸長率增加7%, 強塑積可達25435 MPa·%.形變后殘余奧氏體體積分數由7.8%提高到8.99%, 殘余奧氏體中碳質量分數由1.05%提高到1.31%.
- 兩相區保溫-淬火-配分-貝氏體區等溫工藝 /
- 兩相區形變 /
- 位錯增殖 /
- 殘余奧氏體 /
- 強塑積
Abstract: Hot deformation is a way to effectively improve strength and plasticity of multiphase steels simultaneously, thereby, improving mechanical properties of multiphase steels. Hot deformation affects martensitic transformation mechanism, microstructure, and mechanical properties because it increases retained austenite content and improves stability of multiphase steels. Moreover, hot deformation plays a role in dislocation multiplication, and fine grain strengthening; it can reduce bainite transformation driving force, reduce bainite transformation point, and result in small multiphase organization after quenching-partitioning process. The result can significantly improve the properties of materials. The effects of high-temperature deformation on the stability of room-temperature microstructure, mechanical property, and retained austenite under treatment of IQ&PB (intercritical annealing-quenching and partitioning within the bainitic region) and DIQ&PB (intercritical deformation-intercritical annealing-quenching and partitioning within the bainitic region) processes were studied using scanning electron microscopy (SEM), transmission electron microscope (TEM), electron probe X-ray microanalyser (EPMA), X-ray diffraction (XRD), and tensile testing machine. The results show that dislocation density increases from 0.290×10¹⁴ to 1.286×10¹⁴ m^-2 after 15% compression deformation, and the respective concentrations of C and Cu element enrichment in martensite (the original austenite) increases. Overall, dislocation multiplication produced by high-temperature deformation significantly promotes elemental distribution. After the deformation, the size of bainite lath shortenes and its width increases by 0.1 μm, the volume of the bainite transition increased by 14%, and the size of the polygonal ferrite significantly decreases under the DIQ&PB treatment. In terms of mechanical properties, the tensile strength increases by 132.85 MPa, and the elongation increases by 7%; the strength and ductility product reaches 25435 MPa·% after intercritical deformation heat treatment. The volume fraction of retained austenite increases from 7.8% to 8.99%, and the mass fraction of carbon in the retained austenite increases from 1.05% to 1.31% after compression deformation.
- IQ&PB process /
- intercritical deformation /
- dislocation multiplication /
- retained austenite /
- product of strength and elongation

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圖 1 工藝流程圖. (a) 兩相區保溫-淬火工藝; (b) 兩相區形變后保溫-淬火工藝; (c) 兩相區保溫-淬火-配分-貝氏體區等溫工藝; (d) 兩相區形變后保溫-淬火-配分-貝氏體區等溫工藝

Figure 1. Schematic diagram of heat treatment processes: (a) IQ; (b) DIQ; (c) IQ&PB; (d) DIQ&PB

下載: 全尺寸圖片幻燈片

圖 2 熱處理后試樣透射電鏡照片. (a) IQ工藝; (b) DIQ工藝

Figure 2. TEM images of experimental steels: (a) IQ process; (b) DIQ process

下載: 全尺寸圖片幻燈片

圖 3 IQ與DIQ工藝熱處理后的電子探針圖像. (a、d) 顯微形貌; (b、e) C元素分布情況; (c、f) Cu元素分布

Figure 3. EPMA scanning images of experimental steels treated using IQ and DIQ: (a, d) microstructure; (b, e) C element distribution; (c, f) Cu ele-ment distribution

下載: 全尺寸圖片幻燈片

圖 4 IQ&PB工藝處理后顯微組織照片. (a, b) IQ&PB工藝; (c, d) DIQ&PB工藝

Figure 4. Microstructure images under IQ&PB treatment process: (a, b) IQ&PB process; (c, d) DIQ&PB process

下載: 全尺寸圖片幻燈片

圖 5 IQ&PB與DIQ&PB工藝處理后的X射線圖譜

Figure 5. XRD patterns of experimental steels treated using IQ&PB and DIQ&PB

下載: 全尺寸圖片幻燈片

圖 6 IQ&PB與DIQ&PB工藝處理后的應力-應變曲線

Figure 6. Engineering stress-strain curves of experimental steels treated using IQ&PB and DIQ&PB

下載: 全尺寸圖片幻燈片

圖 7 DIQ&PB工藝處理后距離端口不同位置的X射線衍射能譜圖

Figure 7. XRD patterns of different positions from fracture for experimental steel treated using DIQ&PB

下載: 全尺寸圖片幻燈片

表 1 實驗用鋼的化學成分(質量分數)

Table 1. Chemical composition of experimental steel ?%

C	Si	Mn	Cu	Ni	P	S	B
0.18	1.58	2.06	0.41	0.33	0.008	0.005	0.0017

下載: 導出CSV

表 2 不同熱處理工藝下的位錯密度

Table 2. Measurement results of dislocation density under different heat treatment processes

工藝	位錯密度/(10¹⁴ m^-2)
工藝	視場1	視場2	視場3	視場4	視場5	平均
IQ	0.245	0.296	0.278	0.218	0.412	0.290
DIQ	1.289	1.381	1.357	1.257	1.146	1.286

下載: 導出CSV

表 3 IQ&PB與DIQ&PB工藝的力學性能

Table 3. Mechanical properties of experimental steel under IQ&PB and DIQ&PB treatment processes

熱處理工藝	最大抗拉強度/MPa	斷后伸長率/%	殘余奧氏體體積分數/%	殘余奧氏體中碳質量分數/%	強塑積/(MPa·%)
IQ&PB	1078.36	14	7.80	1.05	14994
DIQ&PB	1211.21	21	8.99	1.31	25435

下載: 導出CSV

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