Effect of Ti Addition on the Microstructure and Mechanical Properties of Cast AZ91 Magnesium Alloy

Ti addition to AZ91 alloy has been investigated with conventional casting. The microstructure and mechanical property were examined. The results show that addition of Ti with an amount of 0.1~0.5%wt resulted in a refinement of the as-cast microstructure. The morphology of β phase is changed from coarse, uneven, semi-continuous skeletal network to small, uniform, short rod-like or granular. When the content of Ti is 0.4wt%, the tensile strength and elongation go up to maximum value of 197 MPa and 6.9% respectively. Small addition of 0.2%wt Ti to AZ91 alloy predominantly forms TiAl3phase, lying in β-phases at the grain boundaries. The mechanism of mechanical properties improvement caused by Ti addition is discussed.

Download Full-text

Effect of Ti on the Mechanical Properties and Corrosion of Cast AZ91 Magnesium Alloy

The Open Materials Science Journal ◽

10.2174/1874088x01206010006 ◽

2012 ◽

Vol 6 (1) ◽

pp. 6-13 ◽

Cited By ~ 13

Author(s):

Xiulan Ai ◽

Gaofeng Quan

Keyword(s):

Mechanical Properties ◽

Az91 Alloy ◽

Weight Loss Measurement ◽

Az91 Magnesium Alloy ◽

Corrosion Resistant ◽

Maximum Value ◽

Az91 Magnesium ◽

Mechanical Properties And Corrosion ◽

Microstructure And Mechanical Property ◽

Ti Addition

Ti addition to AZ91 alloy was been investigated with conventional casting. The microstructure and mechanical property were examined. The Corrosion resistance of all the different Ti addition content alloy was studied in 3.5% NaCl solution through weight loss measurement in constant immersion conditions and potentiodynamic polarization experiments. The results show that addition of Ti with an amount of 0.1~0.5%wt resulted in a refinement of the as-cast microstructure. The morphology of β phases is changed from coarse, uneven, semi-continuous skeletal network to small, uniform, short rod-like or granular. When the content of Ti is 0.4wt%, the tensile strength and elongation go up to maximum value of 197 MPa and 6.9% respectively. The corrosion resistant improved through addition Ti element is related to the morphology and distribute of β phases. The mechanism of mechanical properties and corrosion resistant improvement caused by Ti addition is discussed.

Download Full-text

Effects of Microstructure and Partial Melting on Tensile Properties of AZ91 Magnesium Cast Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.546-549.65 ◽

2007 ◽

Vol 546-549 ◽

pp. 65-68 ◽

Cited By ~ 1

Author(s):

Tian Ping Zhu ◽

Zhan W. Chen ◽

Wei Gao

Keyword(s):

Mechanical Properties ◽

Partial Melting ◽

Tensile Properties ◽

Cast Alloy ◽

Az91 Alloy ◽

Β Phase ◽

Interdendrite Region ◽

Mg17al12 Phase ◽

Az91 Magnesium ◽

Cast Microstructure

Mechanical properties of AZ91 cast alloy depend strongly on the morphology (size and distribution) of the second (β-Mg17Al12) phase. It was observed that low ductility of AZ91 alloy was attributed to the brittle nature of the β phase particles at which microcracks initiated. These microcracks then coalesced contributing to the fracture of alloy. Quantitative study on microcracking progress revealed that cast samples with coarse microstructures fractured at low strain due to the non-uniform distribution of bulk blocky β particles at interdendrite region. These fracture surfaces exhibited clear cleavage mode. Fine cast microstructure presented quasicleavage fracture mode with clear dimple and tear ridges. The partial melting (and resolidification) heat treatment improved tensile properties, which was in disagreement with the available data from literature.

Download Full-text

Effects of CaCO3 Modificator on Microstructure and Mechanical Properties of Cast AZ91 Magnesium Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.546-549.155 ◽

2007 ◽

Vol 546-549 ◽

pp. 155-158

Author(s):

Qu Dong Wang ◽

Yang Zhao ◽

Qing Hua Li

Keyword(s):

Mechanical Properties ◽

Magnesium Alloy ◽

Cleavage Fracture ◽

Tensile Fracture ◽

Az91 Alloy ◽

Az91 Magnesium Alloy ◽

Microstructure And Mechanical Properties ◽

Reticular Structure ◽

Az91 Magnesium ◽

Alloy Increase

Effects of CaCO3 modificator on microstructure and mechanical properties of cast AZ91 Magnesium alloy have been investigated. Tensile fracture behavior of AZ91 alloys modified by CaCO3 has also been studied. Results show that CaCO3 modificator can obviously refine the grain of AZ91 magnesium alloy and Mg17Al12. Mg17Al12 in grain boundary of AZ91 alloy after modified by CaCO3 changes from continuous reticular structure to discontinuous reticular structure, even so much as granular structure and rod structure. After modified by 0.5wt% CaCO3 modificator, ultimate tensile strength, yield strength, impact toughness and elongation of AZ91 alloy increase from 186MPa to 200MPa, from 147MPa to 160MPa, from 4J to 9J and from 2.6% to 5%, respectively. And 0.5wt% CaCO3 modificator brings about an optimal refining effect. The study also shows that the fracture mechanism of modified AZ91 alloy is between cleavage fracture and quasi-cleavage fracture, which is as same as that of unmodified AZ91 alloy.

Download Full-text

Effects of Sr and B addition on microstructure and mechanical properties of AZ91 magnesium alloy

Journal of Materials Research ◽

10.1557/jmr.2007.0331 ◽

2007 ◽

Vol 22 (9) ◽

pp. 2423-2428 ◽

Cited By ~ 15

Author(s):

H.L. Zhao ◽

S.K. Guan ◽

F.Y. Zheng

Keyword(s):

Mechanical Properties ◽

Grain Size ◽

Tensile Strength ◽

Az91 Alloy ◽

Az91 Magnesium Alloy ◽

Solidification Range ◽

Microstructure And Mechanical Properties ◽

Average Grain Size ◽

B Additions ◽

Az91 Magnesium

The effects of Sr and B addition on the microstructure and mechanical properties of AZ91 alloy were studied. The results of this work show that a small amount of Sr addition to AZ91 refined the grain size. The highest tensile strength was obtained from the alloy with the optimal composition of 0.5% Sr and 0.09% B added, in which the average grain size was 42 μm. The tensile strength and elongation of the AZ91–0.5%Sr–0.09%B alloy were 151 MPa and 1.62%, respectively. Some needle-shaped Al4Sr particles distributed mainly at grain boundaries have been observed in the alloys with Sr and B additions. The fluidity is improved significantly, and the solidification range decreased by adding Sr and B. The liquidus of AZ91 alloy decreased markedly with the addition of Sr and B, but the solidus hardly changed. Therefore, the solidification range can be decreased, which will improve the die-casting properties.

Download Full-text

Effect of Ti on Corrosion of Cast AZ91 Magnesium Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.311-313.1457 ◽

2011 ◽

Vol 311-313 ◽

pp. 1457-1461

Author(s):

Xiu Lan Ai ◽

Gao Feng Quan ◽

Jun Yang

Keyword(s):

Galvanic Corrosion ◽

Short Interval ◽

Corrosion Current ◽

Az91 Alloy ◽

Ti Alloy ◽

Az91 Magnesium Alloy ◽

Electrochemical Testing ◽

Immersion Testing ◽

Az91 Magnesium ◽

Ti Addition

Ti addition to AZ91 alloy was been investigated with conventional casting. The Corrosion resistance of all the different Ti addition content alloy was studied in 3.5% NaCl solution through weight loss measurement in constant immersion conditions and potentiodynamic polarization experiments.The results show that addition of Ti with an amount of 0.1~0.8wt% the corrosion resistant of alloy was improved. In the case of AZ91-0.8Ti alloy had minimum corrosion rate value , AZ91-0.4Ti alloy had minimim corrosion current density. After Ti added into alloy, the morphology of β phases was changed, TiAl3intermetallics appeared. The inhibiting effect of the β phases and TiAl3intermetallics in the AZ91-Ti alloy predominated in the long period immersion testing, but during short interval of electrochemical testing galvanic corrosion effect in the AZ91-Ti alloy predominated.

Download Full-text

Effects of La on the Microstructures and Mechanical Properties of AZ91 Magnesium Alloy and its Mechanism

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.328-330.1650 ◽

2011 ◽

Vol 328-330 ◽

pp. 1650-1653 ◽

Cited By ~ 1

Author(s):

Jin Ling Zhang ◽

She Bin Wang ◽

Xiao Ye Qi ◽

Bing She Xu

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Magnesium Alloy ◽

Yield Strength ◽

Maximum Yield ◽

Az91 Alloy ◽

Strengthening Effect ◽

Az91 Magnesium Alloy ◽

Az91 Magnesium ◽

Maximum Yield Strength

Microstructure changes brought by the addition of La element to AZ91 magnesium alloy are studied, also, the precipitating phases were identified and their influence on the mechanical properties of alloys was investigated. Results show La makes refinement of microstructure of the AZ91 alloy, and decrease the size of Mg17Al12 phase. La element takes a priority to react with Al element over Mg, forming binary phase Al11La3 with high melting point. Certain amount of La increases tensile strength, yield strength and elongation. With more addition, La would combine more Al in matrix and decrease strengthening effect, because Al11La3 phase would become coarsening. The mechanical poroerties tests indicate that AZ91+0.16%La alloy has the best properties. Maximum tensile strength, maximum yield strength and elongation are 245MPa, 178MPa and 14.5% respective, increased by 21%, 19% and 48% respectively. The mechanism of La strenthing mechanical properties is proposed that Al11La3 phase enriched on solid-liquid interface, increased the degree of supercooling, refined the grain size and changed the crystal style.

Download Full-text

Effects of Hot Extrusion and Heat Treatment on Mechanical Properties and Microstructures of AZ91 Magnesium Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.562-564.242 ◽

2012 ◽

Vol 562-564 ◽

pp. 242-245 ◽

Cited By ~ 1

Author(s):

Ming Tan ◽

Zhao Ming Liu ◽

Gao Feng Quan

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Tensile Strength ◽

Magnesium Alloy ◽

Solution Treatment ◽

Annealing Treatment ◽

Aging Treatment ◽

Az91 Alloy ◽

Az91 Magnesium Alloy ◽

Az91 Magnesium

The effects of heat treatment on the microstructure, tensile property and fracture behavior of as-extruded AZ91 magnesium alloy were studied by OM and SEM. The results show that the grain of as-cast AZ91 alloy is refined by extruding and dynamic recrystallization, and the mechanical properties increase obviously. The ductility is significantly enhanced after solution treatment of the as-extruded AZ91 alloy, tensile strength is almost the same before and hardness is significantly reduced after solution treatment and artificial aging treatment. The tensile strength reduced and the ductility is significantly enhanced of as-extruded AZ91 magnesium alloy after annealing processes. The fracture surface of as-extruded AZ91 magnesium alloy has the mixture of ductile and brittle characteristic. But after T6 or annealing treatment, its dimple number increases evidently.

Download Full-text

Effect of Modification on Microstructure and Properties of AZ91 Magnesium Alloy

Crystals ◽

10.3390/cryst10060536 ◽

2020 ◽

Vol 10 (6) ◽

pp. 536

Author(s):

Andrzej Kiełbus ◽

Robert Jarosz ◽

Adam Gryc

Keyword(s):

Mechanical Properties ◽

Solid Solution ◽

Magnesium Alloy ◽

Volume Fraction ◽

Az91 Alloy ◽

Carbon Powder ◽

Az91 Magnesium Alloy ◽

Microstructure And Properties ◽

Az91 Magnesium ◽

Cast Magnesium

Refinement of α-Mg solid solution grains has a significant influence on the improvement of mechanical properties of cast magnesium alloys. In the article, the effects of three modifiers on microstructure and properties of AZ91 magnesium alloy casted to a sand mould were described. Overheating, hexachloroethane and wax-CaF2-carbon powder were applied. The research procedure comprised microstructure analysis by means of light microscopy, scanning electron microscopy and quantitative analysis with AnalySIS Pro® software and mechanical properties’ investigation. The microstructure of AZ91 alloy in the as-cast condition consists of α-Mg solid solution with precipitates of Mg17Al12, Mg2Si and Al8Mn5 phases. It was reported that all applied modifiers cause refinement of α-Mg solid solution grains and a decrease of the volume fraction of α-Mg+Mg17Al12 compound discontinuous precipitates. The best results were obtained in the case of wax-CaF2-carbon powder.

Download Full-text

Investigation of the Influence of Open-Die Forging Parameters on the Flow Kinetics of AZ91 Magnesium Alloy

Materials ◽

10.3390/ma14144010 ◽

2021 ◽

Vol 14 (14) ◽

pp. 4010

Author(s):

Grzegorz Banaszek ◽

Teresa Bajor ◽

Anna Kawałek ◽

Tomasz Garstka

Keyword(s):

Magnesium Alloy ◽

Operation Time ◽

Strength Properties ◽

Hydraulic Press ◽

Az91 Alloy ◽

Az91 Magnesium Alloy ◽

Numerical Tests ◽

Az91 Magnesium ◽

Product Manufacturing ◽

Open Die Forging

This paper presents the results of numerical tests of the process of forging magnesium alloy ingots (AZ91) on a hydraulic press with the use of flat and proprietary shaped anvils. The analysis of the hydrostatic pressure distribution and the deformation intensity was carried out. It is one of the elements used for determining the assumptions for the technology of forging to obtain a semi-finished product from the AZ91 alloy with good strength properties. The aim of the research was to reduce the number of forging passes, which will shorten the operation time and reduce the product manufacturing costs. Numerical tests of the AZ91 magnesium alloy were carried out using commercial Forge®NxT software.

Download Full-text