Solid–liquid structural break-up in M2 tool steel for semi-solid metal processing
39
Citation
13
Reference
10
Related Paper
Citation Trend
Keywords:
Thixotropy
Liquation
Sima
The effects of processing parameters of semi-solid billets preparation,reheating temperature and holding time on the semi-solid slurry microstructure of AlSi7MgBe alloy by liquidus semi-continuous casting were studied.And the thixoforming feasibility of semi-solid AISi7MgBe alloy was investigated by analyzing the microstructure and properties of formed parts. The results showed that the microstructure is mainly the homogeneously fine rosette-shaped grains.The microstructure of the billets reheated at 595℃and held for 15 min are near-spherical grains suitable for semi-solid thixoforming.The semi-solid thixoformed parts of AlSi7MgBe alloy are clean-cut,compact and able to fulfill themselves through thixoforming which improves the microstructure and properties.Compared with the liquid forged castings,the hardness of SSM (semi-solid metal)forged castings is increased by 20%.
Liquidus
Sima
Thixotropy
Cite
Citations (0)
The effect of AISi7Mg alloy slurry microstructure in semi-solid zone on the compression deformation was described in the paper. Semi-solid AISi7Mg alloy slurry viscosity depends on alloy initial microstructure variables. The initial microstructure variables of AISi7Mg alloy slurry include the degree of agglomeration among solid particles, particle size, and size distribution and particle morphology. These microstructure variables control the inherent constitutive thixotropic behavior of semi--solid AISi7Mg alloy slurry.
Thixotropy
Cite
Citations (0)
Cite
Citations (141)
Semi-solid CuSn10P1 alloy billets were fabricated by strain induced melt activation(SIMA) method including the forging and remelting processes.Firstly,CuSn10P1 billets were annealed and forged.Secondly,the billets were reheated to 850℃ or 950℃,and hold for 5 min.Finally,the billets were water quenched,and semi-solid microstructures of CuSn10P1 alloy were obtained.The microstructures of semi-solid CuSn10P1 alloy with different stages were observed by OM and SEM.The solid fractions of the semi-solid microstructure were computed.The effects of deformation and remelting temperature on the microstructures of semi-solid CuSn10P1 alloy were investigated.The results indicate that dendritic structure of CuSn10P1 billets is eliminated,and equiaxed grains of a phase are obtained after annealing at 680℃ for 24 h.The solid fraction of semi-solid CuSn10P1 microstructure decreases with the increase of the deformation.With the increase of the deformation from 8.4%to 21.9%,the solid fraction decreases from 70.15%to 57.83%by remelting at 850 ℃,and the solid fraction decreases from 58.79%to 53.10%by remelting at 950 ℃.The higher the remelting temperature is,the smaller the effect of deformation on solid fraction is.
Sima
Equiaxed crystals
Cite
Citations (1)
Precipitation hardened nickel-based superalloys are widely used in aero and industrial gas turbine engines due to their excellent high temperature strength and remarkable hot corrosion resistance. A drawback of many of these alloys is that they are very difficult to weld due to their high susceptibility to heat affected zone (HAZ) cracking, both during welding and post weld heat treatments (PWHT). Weld cracking in many of these alloys has been attributed mostly to constitutional liquatioin of grain boundary NbC precipitates. however, HAZ cracking has been observed in carbon-free superalloys as well, Therefore, research was initiated to examine grain boundary liquation and cracking in HAZs in a variety of Ni-based superalloys. It was found that intergranular cracking of grain boundaries involved liquation of several other phases, in addition to NbC, that were present in pre-weld microstructure of the alloy. These even included the primary strengthening phase,γ’, in a very widely used superalloy, Inconel 738. In addition, segregation of melting point depressant element B was also observed at gain boundaries in other superalloys, which also caused grain boundaries in HAZ to liquate and resulting in their cracking. An overview of microstructural aspects of different liquation phenomena involved and characteristics of the liquid film contributing to the HAZ microfissuring of nickel superalloys will be discussed in this presentation
Liquation
Inconel
Cite
Citations (32)
The present work was undertaken to examine the mechanism in the improvement of HAZ cracking susceptibility of cast alloy 718 welds by addition of rare earth metals (La, Ce). The HAZ cracking susceptibility of La, Ce-added specimens have been discussed in terms of the intergranular liquation, microconstituents and impurity segregation at grain boundaries. The isothermal liquation test result suggested that, in the case of specimens with up to 0.3 mass% La and Ce, the reduced HAZ cracking susceptibility could be attributed to the decrease in intergranular liquation. The microscopic observation revealed that the cause of reduced intergranular liquation in La and Ce containing specimens was responsible for the reduction in the amount of laves cluster and sulfur segregation at grain boundaries due to grain-refining and sulfur-scavenging effects of La and Ce. Furthermore, the increased HAZ cracking susceptibility and grain boundary liquation at over 0.3 mass% La and Ce addition was due to the increase in low-melting point Ni7La2 and Ni2Ce present at grain boundaries.
Liquation
Weldability
Cite
Citations (7)
The microstructure of 25 12 austenitic heat resistant cast steel microalloyed with N, Nb and Re has been studied. The microstructure of quench tempered steel consists of dendritic austenite matrix containing M 23 C 6 secondary carbides. Microstructure of the specimen taken from the burner nozzle after service consists of M 23 C 6 carbides, nitri carbides and σ phase.
Microalloyed steel
Tempering
Cite
Citations (0)
Cite
Citations (51)
Discussing the reaction mechanism of three types of ZL101A? ZL102? GZLSi7MgTi of cast aluminium alloys; testing, analysising and comparing with them in their technique, the chemical composition, the microstructure and the mechnical properties, supply reference treatment technique for producing high strength cast aluminium alloys.
6063 aluminium alloy
Cite
Citations (0)