IMicrostructure evolution and tensile property in the weld heat-affected zone (HAZ) of austenitic Fe-30Mn-9Al-0.9C lightweight steels were investigated. Five alloys with different V and Nb content were prepared by vacuum induction melting and hot rolling process. The HAZ samples were simulated by a Gleeble simulator with welding condition of 300kJ/cm heat input and HAZ peak temperatures of 1150℃ and 1250℃. Microstructures of base steels and HAZ samples were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and their mechanical properties were evaluated by tensile tests. The addition of V and Nb formed fine V and/or Nb-rich carbides, and these carbides increased tensile and yield strength of base steels by grain refinement and precipitation hardening. During thermal cycle for HAZ simulation, the grain growth occurred and the ordered carbide (κ-carbide) formed in the HAZs. The yield strength of HAZ samples (HAZ 1) simulated in 1150℃ peak temperature was higher as compared to the base steel due to the formation of κ-carbide, while the yield strength of the HAZ samples (HAZ 2) simulated in 1250℃ decreased as compared to HAZ 1 due to the excessive grain growth.

No abstract

Trauma is frequently implicated in the development of sarcomas, including rhabdomyosarcoma. Rare soft tissue sarcomas have been reported to arise in scar tissue following surgical procedures or thermal or acid burns, at fracture sites, and in the vicinity of plastic or metal implants, usually after a latent period of several years. The authors encountered a case of a rhabdomyosarcoma arising from the forearm crushed by a conveyor belt 11 years ago. Several possible etiological factors for sarcoma development were identified in this patient, including tissue damage and inflammation, as well as the presence of metal implants and the limb's exposure to radiation during multiple imaging tests. After severe soft tissue damage, the occurrence of a sarcoma should be considered and more attention should be paid to the causative factors for sarcoma.

Percutaneous balloon kyphoplasty is an option for pain relief in pathological vertebral compression fractures. Complications related to cement leakage through cortical defects have been reported. On the other hand, dural compression due to retropulsion of the tumor mass is rarely reported. The authors report a case of a 65-year female patient who had cauda equina syndrome after a percutaneous balloon kyphoplasty in a pathological vertebral fracture, even though epidural compression were not found prior to surgery. Magnetic resonance imaging revealed retropulsion of the tumor mass into the spinal canal through the disrupted posterior vertebral cortex.