The effects of cooling rates on solidification behaviors,segregation characteristics and tensile property of GH4151 alloy were investigated using microstructure characterization and tensile test.Firstly,a relationship...The effects of cooling rates on solidification behaviors,segregation characteristics and tensile property of GH4151 alloy were investigated using microstructure characterization and tensile test.Firstly,a relationship between the secondary dendrite arm spacing and cooling rate was determined and it was confirmed to be valid.Secondly,it can be found from microstructure observations that the morphology of(Nb,Ti)C carbides transits from blocky and script type to fine script type and spotty type,and the refinedγ'phase was observed due to decrease of segregation with increasing cooling rates.Thirdly,the solidification microstructures of the industrial-scale samples were analyzed.The morphology ofηphase changes from indistinguishable shape,fine needle-like shape to large block-like shape with increasing ingot diameter.As a result,the mechanical properties of alloy decrease due to increase of brittle precipitations.The experimental results show that the precipitation behavior of GH4151 is affected by segregation degree of elements,and the segregation degree is determined by solute distribution process and solid back-diffusion process.展开更多
The increasing awareness of climate change has led organizations to demand a standard procedure to measure and communicate greenhouse gas(GHG) emissions linked to their products or services.The publicly available spec...The increasing awareness of climate change has led organizations to demand a standard procedure to measure and communicate greenhouse gas(GHG) emissions linked to their products or services.The publicly available specification PAS 2050 has been developed in response to broad community and industry desire for a consistent method-carbon footprint for assessing the life cycle GHG emissions of goods and services.Specifically,this paper illustrates the implementation of carbon footprint for a baby stroller in accordance with PAS 2050.A fial value of 321 kg per one stroller including package was calculated.Moreover,the study led to identify raw materials production of the stroller as the main source of GHS emissions where efforts need to focus for emission reduction opportunities.This case study is hoped to be a starting point for organizations to benefit from the increasing application of carbon footprint assessment.展开更多
文摘The effects of cooling rates on solidification behaviors,segregation characteristics and tensile property of GH4151 alloy were investigated using microstructure characterization and tensile test.Firstly,a relationship between the secondary dendrite arm spacing and cooling rate was determined and it was confirmed to be valid.Secondly,it can be found from microstructure observations that the morphology of(Nb,Ti)C carbides transits from blocky and script type to fine script type and spotty type,and the refinedγ'phase was observed due to decrease of segregation with increasing cooling rates.Thirdly,the solidification microstructures of the industrial-scale samples were analyzed.The morphology ofηphase changes from indistinguishable shape,fine needle-like shape to large block-like shape with increasing ingot diameter.As a result,the mechanical properties of alloy decrease due to increase of brittle precipitations.The experimental results show that the precipitation behavior of GH4151 is affected by segregation degree of elements,and the segregation degree is determined by solute distribution process and solid back-diffusion process.
基金financially and technically supported by Bugaboo (Xiamen) Companythe Fundamental Research Funds No. 2010121035 for the Central Universities of China
文摘The increasing awareness of climate change has led organizations to demand a standard procedure to measure and communicate greenhouse gas(GHG) emissions linked to their products or services.The publicly available specification PAS 2050 has been developed in response to broad community and industry desire for a consistent method-carbon footprint for assessing the life cycle GHG emissions of goods and services.Specifically,this paper illustrates the implementation of carbon footprint for a baby stroller in accordance with PAS 2050.A fial value of 321 kg per one stroller including package was calculated.Moreover,the study led to identify raw materials production of the stroller as the main source of GHS emissions where efforts need to focus for emission reduction opportunities.This case study is hoped to be a starting point for organizations to benefit from the increasing application of carbon footprint assessment.
