The current work explored additive friction stir deposition of AZ31B magnesium alloy with the aid of MELD?technology.AZ31B magnesium bar stock was fed through a hollow friction stir tool rotating at constant velocity ...The current work explored additive friction stir deposition of AZ31B magnesium alloy with the aid of MELD?technology.AZ31B magnesium bar stock was fed through a hollow friction stir tool rotating at constant velocity of 400 rpm and translating at linear velocity varied from 4.2 to 6.3 mm/s.A single wall consisting of five layers with each layer of 140×40×1 mm^(3)dimensions was deposited under each processing condition.Microstructure,phase,and crystallographic texture evolutions as a function of additive friction stir deposition parameters were studied with the aid of scanning electron microscopy including electron back scatter diffraction and X-ray diffraction.Both feed material and additively produced samples consisted of theα-Mg phase.The additively produced samples exhibited a refined grain structure compared to the feed material.The feed material appeared to have a weak basal texture,while the additively produced samples experienced a strengthening of this basal texture.The additively produced samples showed a marginally higher hardness compared to the feed material.The current work provided a pathway for solid state additive manufacturing of Mg suitable for structural applications such as automotive components and consumable biomedical implants.展开更多
The porous ceramics based on Al2O3-TiO2/ZrO2-SiO2 from particle-stabilized wet foam by direct foaming were discussed.The initial Al2O3-TiO2 suspension was prepared by adding TiO2 suspension to partially hydrophobized ...The porous ceramics based on Al2O3-TiO2/ZrO2-SiO2 from particle-stabilized wet foam by direct foaming were discussed.The initial Al2O3-TiO2 suspension was prepared by adding TiO2 suspension to partially hydrophobized colloidal Al2O3 suspension with equimolar amount,to form Al2TiO5 on sintering.The secondary ZrO2-SiO2 suspension was prepared using the equimolar composition,and to obtain ZrSiO4,ZrTiO4,and mullite phases in the sintered samples,the secondary suspension was blended into the initial suspension at 0,10,20,30,and 50 vol％.The wet foam exhibited an air content up to 87％,Laplace pressure from 1.38 to 2.23 mPa,and higher adsorption free energy at the interface of approximately 5.8×108 to 7.5×108J resulting an outstanding foam stability of 87％.The final suspension was foamed,and the wet foam was sintered from 1400 to 1600 ℃ for 1 h.The porous ceramics with pore size from 150 to 400 μm on average were obtained.The phase identification was accomplished using X-ray diffraction (XRD),differential thermal analysis (DTA),and thermogravimetric analysis (TGA),and microstructural analysis was performed using field emission scanning electron microscopy (FESEM).展开更多
基金the infrastructure and support of Center for Agile and Adaptive Additive Manufacturing(CAAAM)funded through State of Texas Appropriation:190405-105-805008-220。
文摘The current work explored additive friction stir deposition of AZ31B magnesium alloy with the aid of MELD?technology.AZ31B magnesium bar stock was fed through a hollow friction stir tool rotating at constant velocity of 400 rpm and translating at linear velocity varied from 4.2 to 6.3 mm/s.A single wall consisting of five layers with each layer of 140×40×1 mm^(3)dimensions was deposited under each processing condition.Microstructure,phase,and crystallographic texture evolutions as a function of additive friction stir deposition parameters were studied with the aid of scanning electron microscopy including electron back scatter diffraction and X-ray diffraction.Both feed material and additively produced samples consisted of theα-Mg phase.The additively produced samples exhibited a refined grain structure compared to the feed material.The feed material appeared to have a weak basal texture,while the additively produced samples experienced a strengthening of this basal texture.The additively produced samples showed a marginally higher hardness compared to the feed material.The current work provided a pathway for solid state additive manufacturing of Mg suitable for structural applications such as automotive components and consumable biomedical implants.
文摘The porous ceramics based on Al2O3-TiO2/ZrO2-SiO2 from particle-stabilized wet foam by direct foaming were discussed.The initial Al2O3-TiO2 suspension was prepared by adding TiO2 suspension to partially hydrophobized colloidal Al2O3 suspension with equimolar amount,to form Al2TiO5 on sintering.The secondary ZrO2-SiO2 suspension was prepared using the equimolar composition,and to obtain ZrSiO4,ZrTiO4,and mullite phases in the sintered samples,the secondary suspension was blended into the initial suspension at 0,10,20,30,and 50 vol％.The wet foam exhibited an air content up to 87％,Laplace pressure from 1.38 to 2.23 mPa,and higher adsorption free energy at the interface of approximately 5.8×108 to 7.5×108J resulting an outstanding foam stability of 87％.The final suspension was foamed,and the wet foam was sintered from 1400 to 1600 ℃ for 1 h.The porous ceramics with pore size from 150 to 400 μm on average were obtained.The phase identification was accomplished using X-ray diffraction (XRD),differential thermal analysis (DTA),and thermogravimetric analysis (TGA),and microstructural analysis was performed using field emission scanning electron microscopy (FESEM).
