Semi-solid squeeze casting（SSSC） and liquid squeeze casting（LSC） processes were used to fabricate a ZL104 connecting rod, and the influences of the process parameters on the microstructures and mechanical properti...Semi-solid squeeze casting（SSSC） and liquid squeeze casting（LSC） processes were used to fabricate a ZL104 connecting rod, and the influences of the process parameters on the microstructures and mechanical properties were investigated. Results showed that the tensile strength and elongation of the SSSC-fabricated rod were improved by 22% and 17%, respectively, compared with those of the LSC-fabricated rod. For SSSC, the average particle size（APS） and the shape factor（SF） increased with the increase of re-melting temperature（Tr）, whereas the tensile strength and elongation increased first and then decreased. The APS increased with increasing the mold temperature（Tm）, whereas the SF increased initially and then decreased, which caused the tensile strength and elongation to increase initially and then decrease. The APS decreased and the SF increased as squeezing pressure（ps） increased, and the mechanical properties were enhanced. Moreover, the optimal Tr, ps and Tm are 848 K, 100 MPa and 523 K, respectively.展开更多
Due to the influence of mining disturbance stress,it is of great significance to better understand the bearing characteristics of fully grouted bolts under different pull-out loading rates.For this purpose,a series of...Due to the influence of mining disturbance stress,it is of great significance to better understand the bearing characteristics of fully grouted bolts under different pull-out loading rates.For this purpose,a series of laboratory pull-out tests were conducted to comprehensively investigate the effects of different pull-out loading rates on the mechanical performance and failure characteristics of fully grouted bolts.The results show that the mechanical performance of the anchored specimen presents obvious loading rate dependence and shear enhancement characteristics.With the increase of the pull-out loading rates,the maximum pull-out load increases,the displacement and time corresponding to the maximum pull-out load decrease.The accumulated acoustic emission(AE)counts,AE energy and AE events all decrease with the increase of the pull-out loading rates.The AE peak frequency has obvious divisional distribution characteristics and the amplitude is mainly distributed between 50-80 dB.With the increase of the pull-out loading rates,the local strain of the anchoring interface increases and the failure of the anchoring interface transfers to the interior of the resin grout.The accumulated AE counts are used to evaluate the damage parameter of the anchoring interface during the whole pull-out process.The analytical results are in good agreement with the experimental results.The research results may provide guidance for the support design and performance monitoring of fully grouted bolts.展开更多
基金Project(51335009)supported by the National Natural Science Foundation of ChinaProject(2014JQ7273)supported by the Natural Science Foundation of Shaanxi Province of ChinaProject(CXY1514(1))supported by the Xi’an Science and Technology Plan Projects,China
文摘Semi-solid squeeze casting（SSSC） and liquid squeeze casting（LSC） processes were used to fabricate a ZL104 connecting rod, and the influences of the process parameters on the microstructures and mechanical properties were investigated. Results showed that the tensile strength and elongation of the SSSC-fabricated rod were improved by 22% and 17%, respectively, compared with those of the LSC-fabricated rod. For SSSC, the average particle size（APS） and the shape factor（SF） increased with the increase of re-melting temperature（Tr）, whereas the tensile strength and elongation increased first and then decreased. The APS increased with increasing the mold temperature（Tm）, whereas the SF increased initially and then decreased, which caused the tensile strength and elongation to increase initially and then decrease. The APS decreased and the SF increased as squeezing pressure（ps） increased, and the mechanical properties were enhanced. Moreover, the optimal Tr, ps and Tm are 848 K, 100 MPa and 523 K, respectively.
基金Projects(51925402,U1710258,52004172)supported by the National Natural Science Foundation of ChinaProject(20201102004)supported by the Science and Technology Department of Shanxi Province,China。
文摘Due to the influence of mining disturbance stress,it is of great significance to better understand the bearing characteristics of fully grouted bolts under different pull-out loading rates.For this purpose,a series of laboratory pull-out tests were conducted to comprehensively investigate the effects of different pull-out loading rates on the mechanical performance and failure characteristics of fully grouted bolts.The results show that the mechanical performance of the anchored specimen presents obvious loading rate dependence and shear enhancement characteristics.With the increase of the pull-out loading rates,the maximum pull-out load increases,the displacement and time corresponding to the maximum pull-out load decrease.The accumulated acoustic emission(AE)counts,AE energy and AE events all decrease with the increase of the pull-out loading rates.The AE peak frequency has obvious divisional distribution characteristics and the amplitude is mainly distributed between 50-80 dB.With the increase of the pull-out loading rates,the local strain of the anchoring interface increases and the failure of the anchoring interface transfers to the interior of the resin grout.The accumulated AE counts are used to evaluate the damage parameter of the anchoring interface during the whole pull-out process.The analytical results are in good agreement with the experimental results.The research results may provide guidance for the support design and performance monitoring of fully grouted bolts.
