The effect of Cu concentration on the microstructure and mechanical properties of FeCoNiCr-xCu HEAs was investigated. The results showed that low Cu concentrations (less than ∼5 at. %) contributed to a solid solution strengthening effect. The solid solution Cu atom strengthened the yield strength and ultimate tensile strength together. When the Cu concentration reached approximately 7 at. %, larger numbers of nano Cu-rich particle precipitated from the FCC matrix. The nano Cu-rich particle had a strengthening effect and further increased the yield strength and ultimate tensile strength. When the Cu concentration reached approximately 13 at. %, the weak continuous Cu-rich phase formed between dendrites. The early fracture of the Cu-rich phase dramatically decreased the ultimate tensile strength and elongation.

Effect of Cu on the strengthening and embrittling of an FeCoNiCr-xCu HEA

The effect of Cu concentration on the microstructure and mechanical properties of FeCoNiCr-xCu HEAs was investigated. The results showed that low Cu concentrations (less than ∼5 at. %) contributed to a solid solution strengthening effect. The solid solution Cu atom strengthened the yield strength and ultimate tensile strength together. When the Cu concentration reached approximately 7 at. %, larger numbers of nano Cu-rich particle precipitated from the FCC matrix. The nano Cu-rich particle had a strengthening effect and further increased the yield strength and ultimate tensile strength. When the Cu concentration reached approximately 13 at. %, the weak continuous Cu-rich phase formed between dendrites. The early fracture of the Cu-rich phase dramatically decreased the ultimate tensile strength and elongation. 

Multi-particle FEM modeling on hot isostatic pressing of Ti6Al4V powders

The Ti6Al4V alloy castings were produced by the investment casting process, and the hot isostatic pressing (HIP) was used to remove shrinkage from castings. The processing pressure and holding time for HIP were 150 MPa and 20 min, respectively. Four different HIP temperatures were tested, including 750 oC, 850 oC, 920 oC and 950 oC. To evaluate the effects of temperature on densification and microstructure of Ti6Al4V alloy treated by HIP, non-destructive testing and metallographic observation was performed. The experimental results show that the shrinkage was completely closed at 920 oC and 950 oC. The densification of Ti6Al4V alloy increased as the HIP temperature increased below 920 oC. The lamellae were more uniform, the thickness of lamellae was obviously broadened and the structure was coarsen. Besides, the Norton creep equation was used to simulate the effect of different temperatures on the densification of Ti6Al4V alloy during HIP. The simulation results were in good agreement with the experimental results. It was also found that 920 oC is a suitable temperature for HIP for Ti6Al4V alloy.

/pdf/effects-of-hot-isostatic-pressing-temperature-on-casting-3ud5rjhwqt.pdf

Effects of hot isostatic pressing temperature on casting shrinkage densification and microstructure of Ti6Al4V alloy

The objective of the present project was to determine the effects of powder granulation (fraction of grain size) for the Ti-13Nb-13Zr alloy, produced by powder metallurgy, on its porosity, grain co...

Powder metallurgy of the porous Ti-13Nb-13Zr alloy of different powder grain size

2A12 aluminum alloy powders were hot-isostatic-pressed (HIPed) at representative temperatures for investigating the variation in microstructure, tensile property and fracture mode of the powder compact. It was found that the microstructure of raw powders changed from a dendrite structure to an equiaxed structure from room temperature to 600 °C. The liquid phase produced by the eutectic reaction in the powder was gradually increased and finally formed a liquid pathway that ran through the entire powder from 490 to 600 °C. Prior particle boundaries were observed in the powder compacts HIPed at 490 and 520 °C. The liquid phase in the powder compacts was squeezed into the powder boundaries and the triple points of powder when HIPed at 580 °C. However, the liquid phase located at the triple points of the powder was forced out and moved toward a small powder particle by HIP pressure under an HIPing temperature of 600 °C, which led to a decrease in the mechanical properties and relative density. Better comprehensive properties were obtained at HIPing temperatures of 490 and 580 °C. The low ductility exhibited by the P/M aluminum alloy HIPed at different temperatures was believed to arise from a combination of the existence of oxide film on the powder particle surface and the distribution characteristics of the liquid phase. Finally, three typical types of de-cohesion were classified.

Influences of Hot-Isostatic-Pressing Temperature on the Microstructure, Tensile Properties and Tensile Fracture Mode of 2A12 Powder Compact

Hot isostatic pressing (HIP) is an ideal fabrication technique for products with complex structure, but also a reliable post-treatment method. The individual effect of the HIP or HIP post-treatment (HIPPT) on the mechanical properties of powder compacts have been investigated, but little attention has been paid to their combined effect. In this study, the effect of HIPPT on the densification, microstructure and mechanical properties of HIPed powder compacts were investigated. The relative density shows a regional increase after HIPPT. The interlayer spacing of lamellar α phase is increased, equiaxial grains are coarsened and high-angle grains are decreased. Moreover, an obvious increase in elongation is detected, which demonstrates that HIPPT is beneficial to improve the properties of HIPed powder compacts.

Effect of HIP post-treatment on the HIPed Ti6Al4V powder compacts

This paper studied the effects of powder size on densification, microstructure, and mechanical properties of the hot isostatic-pressed 2A12 aluminum alloy powder compact. The results show that the near-fully dense powder compact can be successfully achieved and the smaller the powder is, the higher the relative density is. In addition, as the powder size decreases, the precipitated phases in the powder compact change from continuously point-like distribution at the junctions among powder particles to the concentrated distribution at the three-way intersections. Compared with the large powder, the tensile strength, yield strength, and elongation of the compact with the small powder were improved by 14%, 30.8%, and 48.6%, respectively.

/pdf/effect-of-powder-size-on-microstructure-and-mechanical-4m0nx7pwsf.pdf

Effect of Powder Size on Microstructure and Mechanical Properties of 2A12Al Compacts Fabricated by Hot Isostatic Pressing

This work investigated the effects of the rigid constraint body thickness on the mechanical properties and densification of hot isostatic pressing–produced 2A12 aluminum alloy powder compact. With ...

Effect of the rigid constraint body thickness on aluminum alloy powder compact via hot isostatic pressing

Hot isostatic pressing (HIP) method was used to prepare a composite material consisting of M40JB continuous carbon fibers (Cf) in 2A12 Al alloy powder, to study its mechanical properties and interface bonding situation of composite materials. The microstructure, fracture surface and C f /Al interface characteristics were analyzed by optical microscope(OM), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS).The results show that: the tensile strength and plasticity of the composite increase by 5% and 54% respectively; the fracture mechanism of the composite is brittle fracture; the fractures of the aluminum alloy are along the powder particle interface; carbon fibers are pulled out and fractured in C f /Al interface fracture place; the interfacial reaction of C f /Al mainly occurs between C and Al atoms, and the diffusion reaction product is Al 4 C 3 intermetallic compound.

Xina Huang

Papers

Influences of Hot-Isostatic-Pressing Temperature on the Microstructure, Tensile Properties and Tensile Fracture Mode of 2A12 Powder Compact

Effect of HIP post-treatment on the HIPed Ti6Al4V powder compacts

Effect of Powder Size on Microstructure and Mechanical Properties of 2A12Al Compacts Fabricated by Hot Isostatic Pressing

Effect of the rigid constraint body thickness on aluminum alloy powder compact via hot isostatic pressing

Microstructure and mechanical properties of 2A12 Al alloy powder reinforced with continuous carbon fibers manufactured by hot isostatic pressing