Microstructural evolution of 2026 aluminum alloy during hot compression and subsequent heat treatment

2026 aluminum alloy was compressed in a temperature range of 300-450 ℃ and strain rate range of 0.01-10 s^-1. The correlation between compression conditions and microstructural evolution after solution and aging heat treatment was investigated. It is found that the recrystallization and precipitation behavior after heat treatment are associated with the temperature compensated strain rate Z value during hot deformation. Under low Z parameter condition, a small quantity of free recrystallized grains are formed, and the well formed subgrains with clean high-angle boundaries and coarse precipitates seem to be remained during heat treatment. Under high Z parameter condition, a large number of fine equiaxed recrystallized grains are produced, and a high dislocation density with poorly developed cellularity and considerable fine dynamic precipitates are replaced by the well formed subgrains and relatively coarse precipitates after heat treatment. The average recrystallized grain size after heat treatment decreases with increasing Z value and a quantitative relation between the average grain size and the Z value is obtained.

Research on Tourism Master Planning of Huangshan Hot Spring Scenic Area in China

Based on tourist resources' evaluation and tourism market development of Huangshan Hot Spring Scenic Area,by combining with relevant theories of "SWOT",the paper has identif ied the leading functional orientation and tourism development idea of the hot spring scenic area.Meanwhile,by following the principle of "sustainable use" of Huangshan natural resources,planning strategies and implementing suggestions have been put forward based on "addition,subtraction,multiplication and division".The ultimate purpose is to create diversified tourism experiences for tourists and improve tour quality of hot spring scenic area,and f inally build Huangshan tourism brand of "Snowy Hot Spring".

Evaluation of Tourist's Satisfaction Degree of Dongda Hot Spring Resort Area in Xi'an City

Tourist's satisfaction degree is one of the important indexes to evaluate the service quality of scenic spot.Taking Xi'an Dongda Hot Spring Resort Area for an example,with the expectation difference theory and customers' satisfaction evaluation model as the theoretical basis of the research,the overall satisfaction degree of tourists to hot spring resort area,and the actual sensation accomplishments and the expectation difference of each service index were analyzed by using regression analysis and paired sample t test method.The results showed:① The overall satisfaction degree of tourists to the resort area was higher.There were remarkable correlation among three variables:the sensation value,the overall satisfaction degree,and the tourist's loyalty degree;② Generally,the sensation actual accomplishments of 15 service appraisal factors were higher than the expectation value.According to the characteristics,these 15 service appraisal factors were divided into 5 groups.Some unsatisfactory aspects were found out,and the corrective measures were put forward.

Effect of hot extrusion and heat treatment on microstructure of nickel-base superalloy

Effects of hot extrusion (HEX) and heat treatment on prior particle boundary (PPB), MC carbides,γ′precipitates and grain size of nickel-base FGH96 superalloy were studied. The results show that PPB consists of largeγ′, MC carbides enriched with Ti, Nb and a modicum of oxides. Thereafter, it can efficaciously tune γ′ precipitate size from micrometer down to nanometer region and simultaneously results in the annihilation of PPB by HEX process. The activation energy for grain growth of as-HEXed FGH96 superalloy was measured to be 402.6 kJ/mol, indicating that γ′ precipitate serves the critical role in inhibiting grain growth under sub-solvus heat treatment. Moreover, the results reveal that grain growth is primarily restrained by MC carbide in the case of super-solvus temperature.

Effect of hot working and post-deformation heat treatment on microstructure and tensile properties of Ti-6Al-4V alloy

The effects of hot compression,hot rolling and post-rolling annealing on microstructure and tensile properties of Ti-6Al-4V were analyzed.Hot compression tests were conducted in the temperature range of 800-1 075 °C and at strain rates of 0.001-1 s-1,and the relations between the characteristic points of flow curve and processing variables were developed.Two passes of hot rolling test with total reduction of 75% were performed in the temperature range of 820-1 070 °C and at constant strain rate of 2 s-1.After hot rolling,some specimens were subjected to heat treatment at 870 °C and 920 °C for 2 h followed by air cooling.Hot rolling in beta phase field resulted in coarse beta grains transforming to martensite by cooling.Otherwise,rolling in the alpha/beta phase filed gave rise to a partially globularized alpha microstructure.The post-rolling heat treatment completed the partial globularization of alpha phase in two-phase region and otherwise broke down the martensitic structure of beta-rolled samples.Tensile tests showed that the strength characteristics as well as elongation decrease significantly with increasing the rolling temperature from the two-phase to the single-phase region.Increasing heat treatment temperature contributed to lower strength for the specimens rolled in two-phase region and higher strength characteristics for the beta-rolled specimens.

Morphology and quantitative analysis of O phase during heat treatment of hot-deformed Ti_2AlNb-based alloy

A 1040°C-hot-deformed Ti_2AlNb-based alloy solution-treated at 950°C and aged at different temperatures was quantitatively investigated. The microstructure, size of the phase, and microhardness of the deformed alloys were measured. The results indicated that the microstructure of the deformed Ti_2AlNb-based alloy specimens comprise coarse O lath, fine O lath, equiaxed O/α_2, and acicular O phase. More O phase was generated in the deformed alloy after heat treatment because the acicular O phase was more likely to nucleate and grow along the deformation-induced crystal defects such as dislocations and subgrain boundaries. After deformation and subsequent heat treatment, the acicular O phase of the resultant alloy became finer compared to that of the undeformed alloy, and the acicular O phase became coarser and longer with the elevated aging temperature, while the width of the O lath exhibited unobvious variations. The hot deformation facilitated the dissolution of the O lath but accelerated the precipitation of the acicular O phase. When the 950°C-solution-treated deformed Ti_2AlNb-based alloy was then aged at 750°C for different periods, the phase content was nearly invariable, O and B2 phases eventually reached equilibrium, and the microstructure became stable and homogeneous.

Effect of solution treatment time on plasticity and ductile fracture of 7075 aluminum alloy sheet in hot stamping process

The effect of solution treatment time on the post-formed plasticity and ductile fracture of 7075 aluminum alloy in the hot stamping process was studied.Tensile tests were conducted on the specimens subjected to the hot stamping process with different solution treatment time.The digital image correlation(DIC)analysis was used to obtain the strain of the specimen.Based on the experiments and modeling,the Yld2000-3d yield criterion and the DF2014 ductile fracture criterion were calibrated and used to characterize the anisotropy and fracture behavior of the metal,respectively.Furthermore,the microstructure of specimens was studied.The experimental and simulation results indicate that the 7075 aluminum alloy retains distinct anisotropy after the hot stamping process,and there is no obvious effect of extending the solution treatment time on the material anisotropy.However,it is found that a longer solution treatment time can increase the fracture strain of the aluminum alloy during the hot stamping process,which may be related to the decrease of the second-phase particles size.

Influence of Different Surface Treatments of H13 Hot Work Die Steel on Its Thermal Fatigue Behaviors

Thermal fatigue checking is the general failure of hot work die steels, which is relative with the structures and properties of the steels and the stress alternated during the employment. The Uddeholm test method on thermal fatigue is used to compare the behaviors of different samples, which are treated with plasma nitriding、plasma sulfur carbon nitriding、boronizing or not treated. The results show that the nitriding improves the thermal fatigue property of the tool steel, while the plasma sulfur carbon nitriding and the boronizing impair the property. The mechanisms are induced as follows. By increasing the hardness and changing the stress distribution in the surface layer, surface treatment can decrease the plastic deformation and the tensile stress during the cycling. Therefore, the generation and growth of the cracks are restrained. On the other hand, as results of surface treating, in the surface layer the toughness declines and the expanding coefficient ascendes; the latter change caused the strengthening of the tensile and compressive stress during the cycling. Thus the resistance to thermal fatigue is weakened. Whether or not the surface treatment is favor to thermal fatigue of tool steels relies on which factor is dominant.

Saddle-Dolomite-Bearing Fracture Fillings and Records of Hot Brine Activity in the Jialingjiang Formation,Libixia Section,Hechuan Area of Chongqing City

Most vein minerals deposited in fractures of the Jialingjiang Formation from Libixia section, Hechan area include a large amount of saddle dolomite and accompanying celestite, calcite and fluorite. This study analyzed the nature, source, evolution of the fluids by plane-light petrography, fluid-inclusion methods, cathodoluminescence images, and stable isotopic compositions. The homogenization temperatures of two-phase aqueous fluid inclusions in dolomite range between 100 and 270℃. Combined with the jlSO data, it is suggested that the fluid responsible for the precipitation of fracture fillings have δ18O values between 10%o and 18‰ （relative to SMOW）. The saddle dolomite and the accompanying minerals were the result of activity of dense brines at elevated temperatures. Moreover, analysis shows that the fluid was derived from a mixture of marine-derived brine and deeper circulating flow. This fluid was enriched in Sr during diagenesis and formed celestite in fracture and for regional mineralization. Dissolution of saddle dolomite was attributed to the cooling of Mg/Ca-decreased fluids, which may relate to a leaching of gypsum to celestite in surrounding carbonates.

Vacuum Treatment for Simultaneous Desulphurization and Dephosphorization of Hot Metal and Molten Steel

The vacuum treatment for simultaneous desulphurization and dephosphorization of hot metal and molten steel with pre-melted CaO-based slag was carried out.For pre-treatment of hot metal,both desulphurization and dephosphorization are improved with the increase of CaO in slag,but deteriorated with the increase of CaF2 in slag.The average desulphurization and dephosphorization rate is 68.83 % and 78.46 %,respectively.For molten steel,the substitution of BaO for CaO in slag has minor effect on simultaneous desulphurization and dephosphorization.The desulphurization and dephosphorization rate is higher than 90% and 50% respectively with the lowest final sulfur and phosphorus mass percent being 0.001 2% and 0.010%,respectively.The overall effect of simultaneous desulphurization and dephosphorization of molten steel is better than that of hot metal.

APPLICATION OF RARE EARTH IN SURFACE HEAT TREATMENT OF HOT-WORKING DIE STEELS

This paper studies a compound treatment. i. e. liquid S , N,C co-diffusing with rare earth (RE) and then oxidization , for hot-working die steels , and the effect of RE on thermal fatigue behavior of the diffused layer. XRD and SEM energy spectrum prove that trace RE element actually penetrates into the surface layer of steels. The result shows that RE can reduce the gradient of change of hardness in diffused layer, improve the morphology and distribution of compounds , and reduce the degree of surface alligator crack for thermal fatigue. The behavior of thermal fatigue of hot-working die steels is raised by 70% or so after the application of RE. The effect of RE is analysed according to the theory.

Synergistic Influence of Pre-Harvest Calcium Sprays and Postharvest Hot Water Treatment on Fruit Firmness, Decay, Bitter Pit Incidence and Postharvest Quality of Royal Delicious Apples (<i>Malus x domestica</i>Borkh)

Experiments were conducted to observe the effect of pre-harvest calcium (Ca) applied as calcium chloride (1% W/V) and postharvest hot water treatment (HWT) on “Royal Delicious” apples. For this, apples were divided in 4 lots viz., untreated (neither Ca nor HWT), Ca alone (pre-harvest 3 sprays of CaCl2 (1.0% w/v) in the orchard), HWT (42℃ for 2 h). Apples of all four lots were stored in cold storage maintained at 0℃ ± 1℃ and 90% - 95% relative humidity for 6 months. After storage, fruits were removed to ambient conditions for 5 days, and then observations on decay area and incidence, bitter pit incidence, fruit Ca content, lipoxygenase (LOX) and antioxidant (AOX) activity, fruit firmness and fruit quality parameters were recorded. After 6 months in cold storage plus 5 day at 22℃ ± 2℃ and 70% + 4% RH, apples, which received Ca as pre-harvest spray or those which received postharvest hot water treatment or Ca + HWT had significantly lesser decay area (decay lesions) caused by Penicillium expansum or Botrytis cinerea than untreated ones (control). Ca + HWT treatment was significantly more effective on B. cinerea than P. expansum. Untreated apples exhibited higher incidence of bitter pit (18.2%) than those treated with Ca or HWT or both. Fruit Ca content (2.92% DM) were significantly lower and conversely the LOX activity (6.9 μmoles min–1×g–1FW) was higher in untreated apples. Similarly, total phenolics and AOX activity were also lower in the untreated apples than Ca or HWT treated. HWT or Ca treated apples have beneficial effects on fruit firmness, peel colour and quality parameters like TSS and ascorbic acid content. Thus, it is concluded that pre-harvest sprays of calcium chloride with postharvest HWT is highly useful for “Royal Delicious” for reducing decay loss, maintaining firmness, high levels of antioxidants and fruit quality.

Influence of melt-treatment on material constants of aluminum sheet used for easy-open can during hot deformation

The isothermal compression test at elevated temperature was carried out for aluminum sheets prepared by different melt-treatment methods with aid of dynamic hot/mechanical simulation experimental technology. The material constants of hot deformation have been solved by multivariate regression directly. Influence of metallurgy factors on the constants was analyzed. The results show that at some strain, the relationship of sheets’ flow stress with deformation temperature and strain rate can be expressed more suitably with Arrhenius equation modified by hyperbolic sine function. Structure factor A1, stress-level coefficient α, strain rate sensibility exponent m and deformation activation energy Q all increase with increment of strain, while stress exponent n decreases gradually. The bigger α value or the smaller n value is, the more obvious the dynamic softening is, but the α value will increase for the metallurgy defects existing in the sheets. Influence of melt-treatment on Q depends upon the synthesis effect of all kinds of metallurgy defects. The Q and n values of the sheet prepared by high-efficient melt-treatment are the least, while the m value is the biggest, and the sheet can deform easily and evenly.

Influence of Production Sequence of Aluminum Alloy Hot Rolling on Strip Surface Quality

With the intensification of market competition in the aluminum alloy strip processing industry,it is dif-ficult to control the mass production of the same specifications,which is bound to affect the hot rolling production.This paper studied the effect of the hot rolling order of aluminum alloy on the surface quality of strip,such as roll printing,color difference,anodic oxidation,etc.,reasonable discharge sequence and corresponding optimization measures were formulated.

Influence of thermo hydrogen treatment on hot deformation behavior of Ti600 alloy

Hot compressive deformation of Ti600 alloy after thermo hydrogen treatment (THT) was carried out within hydrogen content range of 0-0.5%, temperature range of 760-920 ℃ and strain rate range of 0.01-10 s-1. The flow stress of Ti600 alloy after THT was obtained under hot deformation condition, and the influence of hydrogen on work-hardening rate (S*), strain energy density (U*), and deformation activation energy (Q) was analysed. The results show that the flow stress of Ti600 alloy decreases remarkably with the increase of hydrogen when the hydrogen content is less than 0.3%. Both S* and U* decrease with the increase of hydrogen when the hydrogen content is less than 0.3%, and when the hydrogen content is more than 0.3%, S* and U* increase with hydrogen addition. The value of Q decreases with the increase of strain at the same hydrogen content. The addition of small quantity of hydrogen leads to an increase of Q at small strain values, and when the strain reaches 0.6, the value of Q decreases gradually with the increase of hydrogen. When the hydrogen content is within the range of 0.1%-0.3%, the flow stress of Ti600 alloy is decreased when being deformed at the temperature range of 760-920 ℃.

“FENG QI AI” HOT COMPRESS TREATMENT

Hot medicated cornpress treatment belongs to an external treatment and is a kindof moxibustion. ″Feng Qi Ai″ prescription was recorded in Yi Fang Lei Ju. Zhu Xu Men, Rui ZhuTang Fang. In the treatment, pain in the loin and the knees, cold-pain around the navel and in theabdornen,diarrhea due to deficiency and cold and other diseases are treated by combination of drugswith hot compress- We have irnproved the treatment and extended the range of its indication. It wasused for treatment 0f menorrhalgia due to cold uterine, gastralgia due to coId of rniddle-jiao, sciatica’periarthritis of shoulder, systremma,piriformis syndrome with good results.

Effect of Hot Water Treatment on Postharvest Shelf Life and Quality of Broccoli

Broccoli was stored at 0, 10, or 20℃after immersion in hot water (38 - 52℃) for 10 or 30 min. Yellowing of broccoli was significantly slowed and shelf life significantly increased when broccoli was treated with hot water at 42 - 46℃and then stored at 10 or 20℃. Heat injury occurred when treatment was higher than 46℃in some varieties. Broccoli lasted 2-3 days longer when stored at 10℃ and 1-2 days longer when stored at 20℃ after hot water treatment at 46℃. There was no significant effect of treatment on shelf life after long time storage at 0℃. Weight loss was reduced by hot water treatment and the respiration behavior of the broccoli was also changed.

Hot Corrosion Resistance of TB8 Titanium Alloy after ECAP and Heat Treatment

The metastableβtitanium alloy TB8(Ti-12.76Mo-2.13Nb-2.73A1-0.16Si)was used as the original material,and the secondary processing method combining equal channel angular pressing(ECAP)and heat treatment was adopted.With the help of optical microscope(OM),scanning electron microscope(SEM)and X-ray diffractometer(XRD),the corrosion behavior of TB8 titanium alloy after different secondary processing(800℃/850℃solid solution-520℃aging,ECAP-800℃/850℃solid solution-520℃aging,and800℃/850℃solid solution-ECAP-520℃aging)was studied.The experimental results show that the hot corrosion products of the six samples are similar,mainly Na_(2)Si_(2)O_(5),MoS_(2),TiCl_(2),Ti(SO_(4))_(2),and TiS.Due to the grains of the TB8 titanium alloy treated by 850℃solid solution-ECAP-520℃aging are obviously refined,the surface structure is the most smooth and dense,forming a continuous Al2O3protective film,and the surface defects are the least after corrosion.Its corrosion layer thickness is the lowest(102.3μm),only 36.5%-81.4%of that of other secondary processing titanium alloys.In addition,the corrosion kinetics curves of the six materials all follow parabolic laws,and the minimum corrosion weight gain of the samples after 850℃solutionECAP-520℃aging treatment is 0.7507 mg·mm^(-2),showing better hot corrosion resistance.

Three-dimensional S-wave velocity structure of the upper crust in the Guangdong-Hong Kong-Macao Greater Bay Area:insights into the basins structure and genesis of hot springs

As one of the four largest bay areas with strong economic activities in the world,the Guangdong-Hong Kong-Macao Greater Bay Area(GHMGBA)is located in the zone of interaction between the South China Block(SCB)and the South China Sea(SCS).Under the influence of complex geologic evolution,basin-range structures,fault systems and hot springs are well developed here.However,the characteristics of geological structures and the genetic mechanism of these geological phenomena are still unclear.Therefore,we performed ambient noise tomography to obtain 3-D upper crust(0-7.5 km)S-wave velocity structures of the GHMGBA by using 40-day continuous waveform data from 130 seismic stations in the GHMGBA.Our results show that sedimentary basins in the GHMGBA are mainly characterized by low-velocity anomalies.S-wave velocities of sediment formation in basins are about 2.8-3.1 km/s.Rapid changes in velocity appear at the edges of the basins,which correspond to the NE-,NEE-,and NW-trending faults,indicating prominent basin-controlling effects of the faults.The Sanshui Basin(SSB),the largest in the GHMGBA,has a developmental depth of about 4 km,and there is a significant difference in velocity gradient between the east and west sides of the basin,indicating that SSB has experienced east-west asymmetric expansion.Moreover,there are prominent low-velocity anomalies at a depth of about 4.5 km beneath the hot springs at the west of the Zhujiang(Pearl)River estuary(ZRE).We infer that the low-velocity anomalies are fluid reservoirs of the hot springs,which lead to the development of the hot springs on the surface.In addition,the distribution of main cities in the GHMGBA shows a spatial correlation with low-velocity areas at shallow depths(<3 km).The population development trend in the GHMGBA in the past 20 years is also mainly concentrated in the structural province of relatively low-velocity.In combination with the GHMGBA basin structures and drainage distribution characteristics,we suggest that the basic geological environment to some extent affects the habitability of the human settlement and thus determines the distribution and development trend of the main urban context.We believe that the 3-D S-wave velocity structure of the upper crust of the GHMGBA obtained in this study,as well as the deep structural characteristics of the basins and hot springs,will provide support to urban construction planning and geological hazards research of the GHMGBA.

Evaluating Infrared Thermal Image’s Color Palettes in Hot Tropical Area

The use of Infrared Thermal Scanners proved to be very useful in lots of applications. Using different color palettes, temperatures can be well-represented in the resulting image. However, most color palettes in hot tropical places like the Philippines are unsuitable since the ambient temperature is almost the same as the scanned object or person. This study evaluates twelve (12) known and used color palettes in the market to determine the most suitable for tropical places using the edge/border tracing algorithms Sobel-Feldman and Laplacian. The result shows that color palettes with the most colors produce more noise, making it difficult to distinguish the object scanned from the background. On the other hand, color palettes with three or fewer contrasting colors produce crisp and more detailed results. This study helps developers and researchers efficiently use color combinations suitable for hot weather for an effective thermal scanning and image representation.