scholarly journals Densification of wood veneers combined with oil-heat treatment. Part 1: Dimensional stability

BioResources ◽  
2010 ◽  
Vol 6 (1) ◽  
pp. 373-385
Author(s):  
Chang-Hua Fang ◽  
Alain Cloutier ◽  
Pierre Blanchet ◽  
Ahmed Koubaa ◽  
Nicolas Mariotti
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Populus Tremuloides ◽  
Dimensional Stability ◽  
Large Wood ◽  
Wood Veneer ◽  
Compression Set ◽  
Compression Direction ◽  
Long Duration ◽  
Biological Attack

is often a problem due to compression recovery. Alternatively, oil-heat treatment (OHT) improves wood dimensional stability and enhances resistance to biological attack. This study examined combined wood densification and OHT. Large wood veneer 700 700 mm specimens prepared with aspen (Populus tremuloides) were densified using heat, steam, and pressure at 160ºC, 180ºC, and 200°C, respectively. OHT at 180, 200ºC, and 220ºC for 1, 2, and 3h was then applied to the densified veneers. Results show that OHT efficiently improved dimensional stability and reduced compression set recovery. OHT temperature and duration markedly influenced the reduction of compression set recovery: the higher the OHT temperature and duration, the lower the recovery. Less than 5% recovery was obtained under various OHT conditions, and almost 0% recovery under some OHT conditions. Radial and tangential swellings of densified veneers were reduced dramatically. Compared to OHT duration, OHT temperature had a pronounced higher impact on radial and tangential swelling. Irreversible swelling (IS) in the compression direction of densified veneers decreased after OHT, particularly with high temperature and long duration, and anti-swelling efficiency (ASE) in the compression direction improved significantly.

Dimensional Stability of Poplar Wood after Densification Combined with Heat Treatment

2012 ◽  
Vol 152-154 ◽  
pp. 112-116 ◽  
Author(s):  
Jia Bin Cai ◽  
Tao Ding ◽  
Liu Yang
Keyword(s):  
Heat Treatment ◽  
Dimensional Stability ◽  
Hybrid Poplar ◽  
Treatment Temperature ◽  
Thermal Modification ◽  
Holding Time ◽  
Poplar Wood ◽  
Compression Set ◽  
Densification Temperature

Hybrid poplar boards were subjected to thermo-mechanical densification combined with heat treatment. Hydroscopicity and hygroscopicity of the treated samples were measured. The results showed that dimensional stability of the samples was influenced by compression set significantly. The higher the compression set, the greater the swelling of the samples. On the contrary, the influence of densification temperature and duration was not significant. Thermal modification significantly reduced hydroscopicity and hygroscopicity of the samples. Both higher treatment temperature and longer holding time resulted in better dimensional stability.

scholarly journals Dimensional stability, fungal resistance and mechanical properties of radiata pine after combined thermo-mechanical compression and oil heat-treatment

Holzforschung ◽  
2016 ◽  
Vol 70 (8) ◽  
pp. 793-800 ◽  
Author(s):  
Manoj Kumar Dubey ◽  
Shusheng Pang ◽  
Shakti Chauhan ◽  
John Walker
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Dimensional Stability ◽  
Linseed Oil ◽  
Treated Wood ◽  
Untreated Wood ◽  
Radiata Pine ◽  
Fungal Resistance ◽  
Compression Set ◽  
Decay Test

Abstract The dimensional stability and mechanical properties of radiata pine (Pinus radiata) has been investigated after thermo-mechanically compression (TMC) followed by oil heat-treatment (OHT). Wood specimens were first compressed in the radial direction then heat-treated in a linseed oil bath at 160–210°C. Spring-back percentage, water repellence efficiencies, and compression set recovery percentage were determined as indicators of dimensional stability. The resistance of treated wood against a brown rot fungi was assessed based on an accelerated laboratory fungal decay test. Strength, stiffness and hardness were determined as a function of different treatment parameters. After TMC, high compression set (39%) was achieved without any surface checks and cracks. Specimens undergoing TMC followed by OHT showed relatively less swelling and low compression set recovery under high moisture conditions. The fungal resistance of wood after TMC+OHT slightly increased compared to untreated wood and TMC wood. The mechanical properties of TMC+OHT wood were inferior to those of TMC wood.

scholarly journals INFLUENCE OF PURITY ON MICROSTRUCTURE AND STRENGTH CHARACTERISTICS OF REFRIGABLE MICROCOMPOSITES

2020 ◽  
pp. 38-43
Author(s):  
N.A. Azarenkov ◽  
V.Е. Semenenko ◽  
S.V. Lytovchenko ◽  
N.G. Styervoyedov
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
High Temperature ◽  
Dimensional Stability ◽  
Structural Materials ◽  
Strength Characteristics ◽  
Crystallization Heat ◽  
Source Materials

The influence of the purity of the source materials on the structural and dimensional stability of micro-composites obtained in the process of controlled invariant phase transformation is investigated. The influence of high-temperature post-crystallization heat treatment on the processes of cleaning and increasing the technological ductility of structural materials is considered. The possibility of their practical use is discussed.

Effect of High Temperature on the Change in Color, Dimensional Stability and Mechanical Properties of Spruce Wood

Holzforschung ◽  
2003 ◽  
Vol 57 (5) ◽  
pp. 539-546 ◽  
Author(s):  
P. Bekhta ◽  
P. Niemz
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Temperature ◽  
Dimensional Stability ◽  
Modulus Of Elasticity ◽  
Bending Strength ◽  
Treatment Time ◽  
Color Difference ◽  
Treatment Temperature ◽  
Color Changes

Summary In this study the effect of high temperature on mechanical properties, dimensional stability and color of spruce was investigated. Wood specimens conditioned at different relative humidities (50, 65, 80 and 95%) were subjected to heat treatment at 200°C for 2, 4, 8, 10 and 24 h and at 100, 150 and 200°C for 24 h. Color changes were measured in the Minolta Croma-Meter CR-300 color system. Bending strength and modulus of elasticity were determined according to DIN 52186. The results show that heat treatment mainly resulted in a darkening of wood tissues, improvement of the dimensional stability of wood and reduction of its mechanical properties. The darkening accelerated generally when treatment temperature exceeded approximately 200°C. Most of the darkening occurred within the first 4 h of exposure. For the specimens heated to high temperatures, the average decrease in bending strength was about 44–50%, while modulus of elasticity was reduced by only 4–9%. We found that treatment time and temperature were more important than relative humidity regarding the color responses. Strong correlations between total color difference and both modulus of elasticity and bending strength were found. Thus, the color parameters can be estimated quantitatively and used as a prediction of wood strength.

Optimizing Solution Heat Treatment to Improve Mechanical Properties of Al Alloy 7055

2007 ◽  
Vol 546-549 ◽  
pp. 877-880 ◽  
Author(s):  
J.H. You ◽  
Sheng Dan Liu ◽  
Z.B. Huang ◽  
Xin Ming Zhang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Aluminum Alloy ◽  
High Temperature ◽  
Solution Heat Treatment ◽  
Al Alloy ◽  
Two Stage ◽  
Second Stage ◽  
Long Duration ◽  
Increasing Temperature

The influence of one- and two- stage solution heat treatment on the microstructure and mechanical properties of aluminum alloy 7055 was investigated. The results showed that in the case of one-stage solution heat treatment in the range of 450 °C to 470 °C, the strength increased while the ductility decreased with temperature. Further increasing temperature led to more dissolution of soluble constituents but a large amount of recrystallization, therefore, the strength decreased while ductility increased. The two-stage solution heat treatment, which included first stage of low-temperature-long-duration and second stage of high-temperature-short-duration heating was suggested for improvement of mechanical properties.

High-Temperature Instability of A Cr2Nb-Nb(Cr) Microlaminate Composite

1996 ◽  
Vol 54 ◽  
pp. 374-375
Author(s):  
M. Larsen ◽  
R.G. Rowe ◽  
D.W. Skelly
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Aircraft Engine ◽  
Lattice Parameter ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Cross Sectional ◽  
Bcc Structure

Microlaminate composites consisting of alternating layers of a high temperature intermetallic compound for elevated temperature strength and a ductile refractory metal for toughening may have uses in aircraft engine turbines. Microstructural stability at elevated temperatures is a crucial requirement for these composites. A microlaminate composite consisting of alternating layers of Cr2Nb and Nb(Cr) was produced by vapor phase deposition. The stability of the layers at elevated temperatures was investigated by cross-sectional TEM.The as-deposited composite consists of layers of a Nb(Cr) solid solution with a composition in atomic percent of 91% Nb and 9% Cr. It has a bcc structure with highly elongated grains. Alternating with this Nb(Cr) layer is the Cr2Nb layer. However, this layer has deposited as a fine grain Cr(Nb) solid solution with a metastable bcc structure and a lattice parameter about half way between that of pure Nb and pure Cr. The atomic composition of this layer is 60% Cr and 40% Nb. The interface between the layers in the as-deposited condition appears very flat (figure 1). After a two hour, 1200 °C heat treatment, the metastable Cr(Nb) layer transforms to the Cr2Nb phase with the C15 cubic structure. Grain coarsening occurs in the Nb(Cr) layer and the interface between the layers roughen. The roughening of the interface is a prelude to an instability of the interface at higher heat treatment temperatures with perturbations of the Cr2Nb grains penetrating into the Nb(Cr) layer.

ALTEMP HX

Alloy Digest ◽  
1993 ◽  
Vol 42 (10) ◽  
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Base Alloy ◽  
Heat Treating ◽  
Nickel Base Alloy ◽  
Temperature Performance ◽  
Nickel Base

Abstract ALTEMP HX is an austenitic nickel-base alloy designed for outstanding oxidation and strength at high temperatures. The alloy is solid-solution strengthened. Applications include uses in the aerospace, heat treatment and petrochemical markets. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness and creep. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, and joining. Filing Code: Ni-442. Producer or source: Allegheny Ludlum Corporation.

INCO ALLOY 330

Alloy Digest ◽  
1992 ◽  
Vol 41 (5) ◽  
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Heat Treating ◽  
High Temperature Alloy ◽  
Nickel Iron ◽  
Temperature Performance ◽  
Inco Alloy ◽  
Iron Chromium

Abstract INCO ALLOY 330 is a nickel/iron/chromium austenitic alloy, not hardenable by heat treatment. It is a solid solution strengthened high-temperature alloy. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-403. Producer or source: Inco Alloys International Inc..

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