Investigation and Modeling of the Preheating Effects on Precipitation and Hot Flow Behavior for Forming High Strength AA7075 at Elevated Temperatures

Investigation and Modeling of the Preheating Effects on Precipitation and Hot Flow Behavior for Forming High Strength AA7075 at Elevated Temperatures

Preheating is the first but critical step for hot stamping high strength precipitate hardened aluminum alloys. To thoroughly understand the effects of preheating conditions—i.e., preheating rate and heating temperature—on the strength and hot deformation of aluminum alloys, a series of thermal–mecha...

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Main Authors: Kailun Zheng, Yong Li, Song Yang, Kunning Fu, Jinghua Zheng, Zhubin He, Shijian Yuan
Format: Article
Language:English
Published: MDPI AG 2020-07-01
Series:Journal of Manufacturing and Materials Processing
Subjects:
aluminum alloy
heating rate
precipitation
flow behavior
hot forming
Online Access:https://www.mdpi.com/2504-4494/4/3/76
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spelling doaj-235625c08bdd4cad817c6bff486eac892020-11-25T03:06:00ZengMDPI AGJournal of Manufacturing and Materials Processing2504-44942020-07-014767610.3390/jmmp4030076Investigation and Modeling of the Preheating Effects on Precipitation and Hot Flow Behavior for Forming High Strength AA7075 at Elevated TemperaturesKailun Zheng0Yong Li1Song Yang2Kunning Fu3Jinghua Zheng4Zhubin He5Shijian Yuan6Department of Mechanical Engineering, Dalian University of Technology, Dalian 116024, ChinaDepartment of Mechanical Engineering and Automation, Beihang University, Beijing 100191, ChinaDepartment of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001, ChinaDepartment of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001, ChinaDepartment of Mechanical Engineering, Imperial College London, London SW7 2AZ, UKDepartment of Mechanical Engineering, Dalian University of Technology, Dalian 116024, ChinaDepartment of Mechanical Engineering, Dalian University of Technology, Dalian 116024, ChinaPreheating is the first but critical step for hot stamping high strength precipitate hardened aluminum alloys. To thoroughly understand the effects of preheating conditions—i.e., preheating rate and heating temperature—on the strength and hot deformation of aluminum alloys, a series of thermal–mechanical tests was performed to determine the post-hardness evolution and hot flow behaviors. Typical microstructures with different preheating conditions were also observed through transmission electron microscopy (TEM), with which a unified model of both hot flow and strength based on key microstructural variables was developed, enabling the successful prediction of macroscopic properties using different preheating strategies. The results have shown that for high strength AA7075 at the T6 condition, the dominant mechanism of precipitate evolution with increasing temperature is the coarsening of precipitates first, followed by dissolution when they exceed a critical temperature. A higher heating rate results in a slower coarsening and a relatively higher strength level. In addition, the flow stress of hot deformation is also higher using a quick heating rate, with more significant softening and reduced ductility.https://www.mdpi.com/2504-4494/4/3/76aluminum alloyheating rateprecipitationflow behaviorhot forming
collection DOAJ
language English
format Article
sources DOAJ
author Kailun Zheng
Yong Li
Song Yang
Kunning Fu
Jinghua Zheng
Zhubin He
Shijian Yuan
spellingShingle Kailun Zheng
Yong Li
Song Yang
Kunning Fu
Jinghua Zheng
Zhubin He
Shijian Yuan
Investigation and Modeling of the Preheating Effects on Precipitation and Hot Flow Behavior for Forming High Strength AA7075 at Elevated Temperatures
Journal of Manufacturing and Materials Processing
aluminum alloy
heating rate
precipitation
flow behavior
hot forming
author_facet Kailun Zheng
Yong Li
Song Yang
Kunning Fu
Jinghua Zheng
Zhubin He
Shijian Yuan
author_sort Kailun Zheng
title Investigation and Modeling of the Preheating Effects on Precipitation and Hot Flow Behavior for Forming High Strength AA7075 at Elevated Temperatures
title_short Investigation and Modeling of the Preheating Effects on Precipitation and Hot Flow Behavior for Forming High Strength AA7075 at Elevated Temperatures
title_full Investigation and Modeling of the Preheating Effects on Precipitation and Hot Flow Behavior for Forming High Strength AA7075 at Elevated Temperatures
title_fullStr Investigation and Modeling of the Preheating Effects on Precipitation and Hot Flow Behavior for Forming High Strength AA7075 at Elevated Temperatures
title_full_unstemmed Investigation and Modeling of the Preheating Effects on Precipitation and Hot Flow Behavior for Forming High Strength AA7075 at Elevated Temperatures
title_sort investigation and modeling of the preheating effects on precipitation and hot flow behavior for forming high strength aa7075 at elevated temperatures
publisher MDPI AG
series Journal of Manufacturing and Materials Processing
issn 2504-4494
publishDate 2020-07-01
description Preheating is the first but critical step for hot stamping high strength precipitate hardened aluminum alloys. To thoroughly understand the effects of preheating conditions—i.e., preheating rate and heating temperature—on the strength and hot deformation of aluminum alloys, a series of thermal–mechanical tests was performed to determine the post-hardness evolution and hot flow behaviors. Typical microstructures with different preheating conditions were also observed through transmission electron microscopy (TEM), with which a unified model of both hot flow and strength based on key microstructural variables was developed, enabling the successful prediction of macroscopic properties using different preheating strategies. The results have shown that for high strength AA7075 at the T6 condition, the dominant mechanism of precipitate evolution with increasing temperature is the coarsening of precipitates first, followed by dissolution when they exceed a critical temperature. A higher heating rate results in a slower coarsening and a relatively higher strength level. In addition, the flow stress of hot deformation is also higher using a quick heating rate, with more significant softening and reduced ductility.
topic aluminum alloy
heating rate
precipitation
flow behavior
hot forming
url https://www.mdpi.com/2504-4494/4/3/76
work_keys_str_mv AT kailunzheng investigationandmodelingofthepreheatingeffectsonprecipitationandhotflowbehaviorforforminghighstrengthaa7075atelevatedtemperatures
AT yongli investigationandmodelingofthepreheatingeffectsonprecipitationandhotflowbehaviorforforminghighstrengthaa7075atelevatedtemperatures
AT songyang investigationandmodelingofthepreheatingeffectsonprecipitationandhotflowbehaviorforforminghighstrengthaa7075atelevatedtemperatures
AT kunningfu investigationandmodelingofthepreheatingeffectsonprecipitationandhotflowbehaviorforforminghighstrengthaa7075atelevatedtemperatures
AT jinghuazheng investigationandmodelingofthepreheatingeffectsonprecipitationandhotflowbehaviorforforminghighstrengthaa7075atelevatedtemperatures
AT zhubinhe investigationandmodelingofthepreheatingeffectsonprecipitationandhotflowbehaviorforforminghighstrengthaa7075atelevatedtemperatures
AT shijianyuan investigationandmodelingofthepreheatingeffectsonprecipitationandhotflowbehaviorforforminghighstrengthaa7075atelevatedtemperatures
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