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hot tearing susceptibility of MgZn_(4.5)Y_xZr_(0.5) alloys and mechanism

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China Foundry 2016年第3期13卷 159-165页

作者： Yu Feng Ping-li Mao Zheng Liu Zhi Wang Jia-ming Qin Feng Wang School of Materials Science and Engineering Shenyang University of Technology

The hot tearing susceptibility of MgZn_(4.5)Y_xZr_(0.5)(x = 0.5, 1, 2, 4, 6) alloys was evaluated using ClyneDavies' theoretical model and a constrained rod casting(CRC) apparatus equipped with a load cell and data acquisition system. The results obtained from these two approaches were in good agreement, illustrating that the hot tearing susceptibility of the investigated alloys is in the order of MgZn_(4.5)Y_xZr_(0.5) > MgZn_(4.5)Y_xZr_(0.5) > MgZn_(4.5)Y_xZr_(0.5) > MgZn_(4.5)Y_xZr_(0.5)> MgZn_(4.5)Y_xZr_(0.5). The microstructure and morphology of hot tearing regions were observed by means of X-ray diffraction and scanning electron microscopy. The function curves on variation of contraction force and temperature versus time were recorded by a computer during solidification of the MgZn_(4.5)Y_xZr_(0.5) alloys in a "T" type mold after A/D(Analog to digital) conversion. Results show that both the amount and morphology of the second phases have a great relationship with the hot tearing susceptibility. But the former plays a more important role on that of MgZn_(4.5)Y_xZr_(0.5) alloys. The role of low-melting point eutectic phases on the hot tearing susceptibility of MgZn_(4.5)Y_xZr_(0.5) alloys changes gradually with different Y contents. When Y ≤ 1wt.%, it is mainly a damaging effect on intergranular bonding force; when Y > 1wt.%, it is mainly an intergranular feeding effect on formed separated dendrites.

关键词： hot tearing susceptibility Mg-Zn-Y-Zr alloys second phases liquid film

Improvement of yttrium on the hot tearing susceptibility of 6TiB_2/Al-5Cu composite

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Journal of Rare Earths 2015年第12期33卷 1335-1340页

作者：张晓波孙靖汪明亮张亦杰马乃恒王浩伟 State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University

To improve the severe hot tearing susceptibility of TiB2 reinforced A1-5Cu matrix composites, the present research investigated the influence of Y on the hot tearing susceptibility of 6TiB2/A1-5Cu composite. For the composite added with Y, the solidification temperature range was shortened, which was caused by the novel rl-A18Cu4Y phase. The grain size of 6TiB2/A1-5Cu composite was 39.8 p.m. The addition of Y promoted the grain refinement, and the grain sizes were 36.33, 33.42 and 26.77 μm for 6TiB2/AI-5Cu with 0.2 wt.%, 0.5 wt.% and 1 wt.% Y, respectively. The decrease of solidification temperature range and grain size was beneficial to the hot tearing susceptibility improvement. Furthermore, the hot tearing initiation force increased from 44 to 288 N, when 1 wt.% Y was added in 6TiB2/A1-5Cu. For the above significant influence, the hot tearing susceptibility values were reduced by 12.2 wt.%, 57.7 wt.% and 66.8 wt.% for 6TiBjA1-5Cu with 0.2 wt.%, 0.5 wt.% and 1 wt.% Y, accordingly.

关键词： metal matrix composites microstructure hot tearing susceptibility rare earths

Effect of addition of minor amounts of Sb and Gd on hot tearing susceptibility of Mg-5Al-3Ca alloy

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Journal of Magnesium and Alloys 2023年第2期11卷 694-705页

作者： Xudong Du Feng Wang Zhi Wang Le Zhou Zheng Liu Pingli Mao School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870P R China Key Laboratory of Magnesium Alloys and the Processing technology of Liaoning Province Shenyang 110870P R China

The effects of addition of minor amount of(0.5 wt.%) antimony(Sb) or gadolinium(Gd) and combined addition of Sb and Gd(0.5 wt.%,respectively) on the hot tearing susceptibility(HTS) of Mg-5Al-3Ca alloy were investigated experimentally using a “T-shaped” hot tearing measuring system. Various solidification parameters of the alloys were measured and calculated through thermal analysis experiments. The microstructure, grain size, and morphology of the crack zone were characterized by scanning electron microscopy and electron backscatter diffraction, and the crystal phases of the alloys were analyzed by X-ray diffraction and energy-dispersive X-ray spectroscopy. The results showed that the addition of 0.5 wt.% Gd resulted in the increase in the vulnerable temperature range(Tv) and reduced the eutectic structure content that could participate in feeding, thereby improving the HTS of the alloy. However, addition of 0.5 wt.% Sb or combined addition of Gd and Sb(0.5 wt.%, respectively) to the Mg-5Al-3Ca alloy shortened the Tvand improved the skeleton strength of the alloy, thereby reducing HTS. Moreover, significantly refined structure of Mg-5Al-3Ca-0.5Gd-0.5Sb alloy improved the feeding ability of the eutectic structure, thus the alloy exhibited the lowest HTS.

关键词： hot tearing susceptibility Mg-5Al-3Ca alloy Thermal analysis Microstructure

Tensile properties and hot tearing susceptibility of cast Al–Cu alloys containing excess Fe and Si

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International Journal of Minerals,Metallurgy and Materials 2021年第4期28卷 718-728页

作者： Khalil Ganjehfard Reza Taghiabadi Mohammad Talafi Noghani Mohammad Hossein Ghoncheh Faculty of Engineering Imam Khomeini International University(IKIU)QazvinIran Department of Mechanical Engineering University of New BrunswickFrederictonNBCanada

This study was undertaken to investigate the tensile properties and hot tearing susceptibility of cast Al–Cu alloys containing excess Fe(up to 1.5 wt%)and Si(up to 2.5 wt%).According to the results,the optimum tensile properties and hot tearing resistance were achieved at Fe/Si mass ratio of 1,where theα-Fe phase was the dominant Fe *** the Fe/Si mass ratio above unity increased the amounts of detrimentalβ-Cu Fe platelets in the microstructure,deteriorating the tensile properties and hot tearing *** the mass ratio below unity increased the size and fraction of Si needles and micropores in the microstructure,also impairing the tensile properties and hot tearing *** investigation of hot-torn surfaces revealed that theβ-Cu Fe platelets disrupted the tear healing phenomenon by blocking interdendritic feeding channels,while theα-Fe intermetallics improved the hot tearing resistivity due to their compact morphology and high melting point.

关键词： aluminum–copper alloys castability fluidity hot tearing susceptibility

hot tearing susceptibility of Mg-xZn-2Y alloys

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Transactions of Nonferrous Metals Society of China 2016年第12期26卷 3115-3122页

作者： Zhi WANG Yi-zhou LI Feng WANG Yuan-ding HUANG Jiang-feng SONG Ping-li MAO Zheng LIU School of Materials Science and Engineering Shenyang University of Technology Shenyang 110870 China

Effects of Zn content (0, 0.5%, 1.5% and 4.5%) on the hot tearing characteristics of Mg?2%Y alloy were studied in aconstrained rod casting (CRC) apparatus attached with a load cell and data acquisition system. The experimental results indicate thatthe hot tearing susceptibility (HTS) is affected by the content of Zn. The Zn-free base alloy shows the lowest HTS. The HTS ofMg?xZn?2Y alloys increases with increasing Zn content, reaches the maximum at 1.5% Zn, and then decreases with further Znaddition. The high HTS observed in the alloy with 1.5% Zn is attributed to its high force release rate and large force drop duringsolidification. The hot cracks of casting are initiated and propagate along the dendritic or grain boundaries. The predictions of HTS ofMg?xZn?2Y alloys using ProCAST software are in good agreement with the results obtained by experimental measurements.

关键词： Mg-xZn-2Y alloy hot tearing susceptibility solidification contraction force numerical simulation

Effect of long-period stacking ordered phase on hot tearing susceptibility of Mg-lZn-xY alloys

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Journal of Magnesium and Alloys 2020年第4期8卷 1176-1185页

作者： Ye Zhou Pingli Mao Le Zhou Zhi Wang Feng Wang Zheng Liu School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China Key Laboratory of Magnesium Alloys and the Processing Technology of Liaoning Province China

The effect of long-period stacking ordered(LPSO)phase on hot tearing susceptibility of Mg-1 Zn-xY serial alloys were investigated experimentally using a home-made T-type hot tearing *** characteristic parameters related to HTS during the solidification process were calculated by thermal *** microstructure and morphology of the crack zone were characterized by optical microscope(OM),scanning electron microscopy(SEM)and electron dispersive spectrometer(EDS),and the phases of the alloys were analyzed by X-ray diffraction(XRD).The result showed that the long-period stacking ordered(LPSO)phase formed when m(Zn)/m(Y)hot tearing refilling and decrease the HTS of the *** in creasing the content of LPSO phase,the HTS of the alloys *** phase increased the skeleton strength,and reduced the HTS of Mg-lZn-xY alloys.

关键词： Mg-Zn-Y alloys hot tearing susceptibility Thermal analysis LPSO phase Numerical simulation

Influence of alloying elements on hot tearing susceptibility of Mg-Zn alloys based on thermodynamic calculation and experimental

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Journal of Magnesium and Alloys 2018年第1期6卷 44-51页

作者： Zhenzhen Yang Ke Wang Penghuai Fu Liming Peng Bin Hu Ming Liu Anil K.Sachdev National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composite Shanghai Jiao Tong UniversityShanghai 200240PR China Shanghai Light Alloy Net Forming National Engineering Research Center Co. Ltd.Shanghai 201615PR China General Motors China Science Laboratory Shanghai 201206PR China General Motors Research&Development Center WarrenMI 48090USA

Based on the hot tearing index|△T/△(fs)^(0.5)|recently proposed by Kou and the thermodynamic calculations of Pandat software,Al,Cu,and Mn elements were picked up and their influence on hot tearing susceptibility of Mg-x Zn(x=6,8,10,wt%)alloys was studied by *** results indicate that Al addition can significantly reduce the hot tearing susceptibility of Mg-Zn *** 0.5Cu or 0.3Mn addition individually can reduce the HTS of the Mg-6Zn-(1,4)Al alloys,while adding together increases the *** addition of 0.5Cu and 0.3Mn both individually and together increases the HTS of Mg-8/10Zn-1Al *** on the experimental and calculation results,the index can be modified to|△T/△(fs)^(0.5)|(d)^(2)for more accurate prediction on the hot tearing resistance of Mg-Zn based *** refinement significantly improves the hot tearing resistance of Mg-Zn based alloys.

关键词： hot tearing susceptibility Mg-Zn Alloying element Thermodynamic calculation Grain size

Solidification pathways and hot tearing susceptibility of MgZn_xY_4Zr_(0.5) alloys

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China Foundry 2018年第2期15卷 124-131页

作者： Zhi Wang Sheng Yao Yu Feng Zheng Liu Yi-zhou Li Feng Wang Ping-li Mao School of Materials Science and Engineering Shenyang University of Technology

hot tearing is known as one of the most serious solidification defects commonly encountered during solidification. It is very important to study the solidification path of alloys. In the work, thermal analysis with cooling curve was used for the investigation of microstructure evolution with different Zn contents during solidification process of MgZn_xY_4Zr_(0.5) alloys. Thermal analysis results of MgY_4Zr_(0.5) alloys revealed one distinct phase precipitation: α-Mg. Three different phase peaks were detected in the Zn-containing alloys: α-Mg, Z-phase(Mg_(12)YZn) and W-phase(Mg_3 Y_2Zn_3). In addition, for the present MgZn_xY_4Zr_(0.5) alloys, the freezing ranges of these alloys from large to small were: MgZn_(1.5)Y_4Zr_(0.5)>MgZn)(3.0) Y)4Zr_(0.5)>MgZn0.5 Y4 Zr0.5>MgY_4Zr_(0.5). The effect of different contents of Zn(0, 0.5, 1.5, 3.0 wt.%) on hot tearing behavior of MgY_4Zr_(0.5) alloy was investigated using a constrained rod casting(CRC) apparatus equipped with a load cell and data acquisition system. The experimental results show that the addition of Zn element significantly increases hot tearing susceptibility(HTS) of the MgY_4Zr_(0.5) alloy due to its extended freezing range. Some free dendrite-like bumps and ruptured liquid films on the fracture surfaces were observed in all the fracture surfaces. These phenomena proved the fact that the hot tearing formation was caused by interdendritic separation due to lack of feeding at the end of solidification.

关键词： MgZnxY4Zr0.5 alloys microstructure thermal analysis hot tearing susceptibility

Influence of a low-frequency alternating magnetic field on hot tearing susceptibility of EV31 magnesium alloy

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China Foundry 2021年第3期18卷 229-238页

作者： Xin Su Zhi-jun Feng Jing-fu Huang Xu-dong Du Ru-shuang An Feng Wang Yan-chun Lou State Key Laboratory of Light Alloy Casting Technology for High-end Equipment Shenyang 110022China Shenyang Research Institute of Foundry Co. Ltd.Shenyang 110022China Shenyang Research Casting Technology Co. Ltd.Shenyang 110141China College of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China

The effect of a low-frequency alternating magnetic field (AMF,0 A 0 Hz,5 A 10 Hz,10 A 10 Hz,15 A 10 Hz) on the hot tearing susceptibility (HTS) of a magnesium alloy (EV31) was systematically studied using a combination of experiment and numerical *** observing the macroscopic hot cracks in hot joints of the "T" samples,the hot tearing tendency of the samples was *** HTS of the alloy can be predicted via numerical simulation and the crack susceptibility coefficient (CSC).The microstructure and morphology of the hot tearing zone of EV31 were investigated using scanning electron microscopy (SEM).Results show that increasing the magnetic field strength reduces both the alloy solidification temperature range and the dendrite coherency temperature,which increases the feeding time during solidification and decreases the HTS of the *** the magnetic field parameters are 10 Hz 15 A,the EV31 alloy shows the lowest *** main component of the second phase in the microstructure is *** study also found that the electromagnetic field can effectively refine the grains,purify the melt,and reduce the oxide content in the *** obtained simulation results are consistent with the experimental results.

关键词： EV31 magnesium alloy electromagnetic field hot tearing susceptibility microstructure dendrite coherency temperature