ABSTRACT In the present investigation, effect of microplasma arc welding (MPAW) process parameters on grain growth and porosity distribution thin sheet Ti6Al4V alloy weldment has been examined. The MPAW procedure was performed at different current, speed, flow rates shielding plasma gas. Metallographic characterization carried out by light microscopy scanning electron (SEM). results have shown that beyond a threshold energy, burn metal in can occur. This case should be considered for any...

Ni–Ti coatings were deposited using APS process. In this regard, mechanically activated powders with amorphous/nanocrystalline structure used. Two different sieved powders, one of nominal size range (–63 to +20 μm) and the other (–125 +63 μm), employed in experiments. The phase composition microstructure examined by X-ray diffraction, optical microscopy scanning electron microscopy. results indicated that for coating produced finer powder, increasing plasma power has caused severe cracking...

An effective technique to improve the stop-band frequency response of direct-coupled resonators in substrate-integrated waveguide (SIW) technology is introduced. Regular inductive-iris filters SIW are supplemented with H-plane frequency-dependent inverters which not only create transmission zeros but also serve as proper impedance inverter. A synthesis introduced prescribe at finite frequencies on either side pass band, symmetrically or asymmetrically. Two different topologies for X-band...

In this study, an attempt has been made to synthesis Mo–Si–B multiphase alloy powder using a combination of mechanical alloying (MA) and various heat treatments. For purpose, Mo–14Si–10B (at.-%) elemental powders pure Mo were separately milled attritor mill. Mechanically alloyed (MAed) annealed in atmosphere controlled furnace under constant temperature with different holding times. Metallurgical characteristics MAed and/or evaluated by SEM, optical microscopy, X-ray diffraction atomic...

A simple, compact, and low-cost implementation of an auto-calibration system for evaluating a Ka-band phased array active element is presented. The proposed technique estimates the amplitude/phase unbalance each antenna induced by feed circuit characterizes phase shifter variable gain amplifier (VGA) attached to individual in configuration. This intelligent calibration employs locked loop (PLL) oscillators generate RF test signal LO signal. former used down-converting output from under...

INVESTIGATION OF THE EFFECT THERMOMECHANICAL PROCESSING ON MICROSTRUCTURE AND CORROSION RESISTANCE 321 AUSTENITIC STAINLESS STEEL

This paper presents a general circuit structure based on piecewise constant approximation method for designing high-rate ultra-wideband (UWB) pulse generators. By changing the duration and number of segments, both bandwidth center frequency UWB signals are tuned. The generator modulates different carrier frequencies into with Gaussian envelop to spread signal spectrum over 3.1-10.6-GHz sub-bands. Also, proposed modulator can be easily adopted generate pulses 528-MHz within three sub-bands in...

A low complexity and cost-effective automated test method for estimation compensation of combined TX/RX IQ imbalance calibration the phased array antenna elements in millimeter wave transceivers integrated with an package has been presented validated. The proposed technique is effective way characterizing phase amplitude imbalances even a DUT (Device Under Test) that does not provide direct access to internal Local Oscillator (LO) or divided version that. high-resolution digital-to-analog...